What is Tachi Samurai from data.pack

[Slamdrunk]

I was scrolling in the data.pack and i noticed unit card that looked a bit like katana samurai and was called tachi samurai... does anyone know what that unit is and can i somehow unlock it from the datas??

[Panzercracker]

Well, Tachi Samurai is the original sword samurai beside No-Dachi Samurai. But they replace Katana Samurai instead Tachi Samurai, because most of people only know katana and think katana always is used on battlefield too while in real history of Sengoku, era katana is used rarely and only use by low-class soldiers.

[Slamdrunk]

How do you know this?

[Panzercracker]

Research history records and ask people around, you will have answer . The media make katana is soul of samurai, but in Sengoku era of Shogun 1,2 TW, sword is just secondary weapons and the samurai's sword is tachi, only low class soldier only use katana because katana is urban sword, not battlefield sword, and those low class soldier is so poor for buy battlefield weapon, so katana is the last option. But thanks to films, manga v.v... most of people mistake katana as full armoured samurai's main weapon. And this game want to become popular for every players, they replace Tachi Samurai (even this unit is unreal) by famous Katana Samurai; that why Shogun 1 TW only have No-dachi Samurai as sword unit, the rest foot infantry is yari, yumi and naginata.

[Triumvere]

Well, Tachi Samurai is the original sword samurai beside No-Dachi Samurai. But they replace Katana Samurai instead Tachi Samurai, because most of people only know katana and think katana always is used on battlefield too while in real history of Sengoku, era katana is used rarely and only use by low-class soldiers.

Sorry, this just isn't true.

The tachi was the precursor to the katana. It was slightly longer, and slightly more curved, and worn with the edge down instead of up. It was replaced by the katana as the primary samurai sword hundreds of years before Sengoku.

[CoconutFred]

Sorry, this just isn't true.

The tachi was the precursor to the katana. It was slightly longer, and slightly more curved, and worn with the edge down instead of up. It was replaced by the katana as the primary samurai sword hundreds of years before Sengoku.

Yeah, Tachi were long swords.

However, cavalry around the time of the Sengoku Period AFAIK still used Tachi as their primary sword.

[Kraxis]

Indeed. Tachis and Katanas are for most part impossible to tell apart as there were long Katanas and shorter Tachis. The only true way to tell them apart would be the scabbard. The Katana scabbard is the wellknown sleek scabbard with cords to tie it into the belt securly. Meanwhile the Tachi scabbard is a lot more elaborate, with metal buttons, clamps, inlays and other ornamental stuff. Also it would have no cords, as it was hung from a seperate attachment of metal that held onto the belt.

As noted, the Tachi was worn edge down, while the Katana was worn edge up. The Katana 'style' came to be when infantry became more important once more. Drawing a sword like a Katana is considerably faster if it is worn like that. However, imagine it on a horse. Drawing a Katana there would run into the problem of the horse's neck. So therefor the Tachi remained in use. Given that the Tachi was a cavalry sword, it is not surprising that it is slightly longer on average. Similarly, while the Katana style meant faster draws, it also limited the length of the blade (you can't really draw it further than your arm's length), so it had to be slightly shorter, which in any case was a very nimble length in any case.

So Tachi Samurai would be an oxymoron in Shogun 2, as the name Samurai would imply it to be an infantry unit, but using a cavalry weapon. However, this didn't stop CA from using Katana Cav which are equally oxymoron (they should be Tachi Cav).

[DeMolay]

Good post Kraxis

indeed , it's ahistorical to use "katana" for cavalrymen . Katanas were produced since as far as the Heian period , and some of the greatest masterpieces were made during the Kamakura period (12th and 13th century ).

They always existed on the battlefield equipping foot infantry before the Sengoku-Jidai , however they were in small numbers (compared to later ) and used only as a secondary weapon ( or even 3rd weapon) because until the mid-16th century , the samurais class mostly fought on horse with a yumi bow and a yari (or both ) , so they always carried the tachi instead as back up , which was more refined (ornaments ) , longer blade and more sori (curvature ) than a katana .

What happened is that after the Onnin Wars , roughly at the end of the 15th century , which saw rebellions of common folks and ikko-ikkis crush samurai armies , Japanese armies from then on were more and more composed of ashigarus , and these masses of ashigarus had to be equipped and trained , so they started crafting more and more cheap uchigatana swords with short blades ( around 65-70cm) . Moreover , since Japan was embroiled in a violent civil war during Sengoku Jidai , the old wisdom about swordmaking of the Muromachi and Kamakura period was partly lost and the focus was more on quantity rather than quality in times of war ( tachi were quality sword destined at the elite , katana were more "quantity" although there are some exceptions when it was made by a famous swordsmith for someone particular ) . Then there is the fact that after the introduction of firearms , cavalry was gradually less prominent on the battlefield which led to a decrease in the amount of tachis

During the 16th century Sengoku Jidai period , the katana saw an extensive use on the battlefield as secondary weapon for foot soldiers , later in the 17th century when Japan was at peace , many tachis were remounted into katanas and blade shortened there are many examples still living today .) , at that point the katana became a distinctive sign of the samurai social class


I think a good read here is this page , which sources stated and overall , always very good articles :

http://wiki.samurai-archives.com/ind...apanese_Swords

[Triumvere]

So Tachi Samurai would be an oxymoron in Shogun 2, as the name Samurai would imply it to be an infantry unit, but using a cavalry weapon. However, this didn't stop CA from using Katana Cav which are equally oxymoron (they should be Tachi Cav).

Eh. I don't entirely agree this assessment.

As you mentioned yourself, katana and tachi are nearly identical. While it is true that the transition from tachi to katana corresponds to the transition from mounted combat to infantry combat, it's not like there is any difficulty in using a katana from horseback. Once again, the swords are almost the same. By Sengoku, the daisho (katana/wakazashi) had replaced the tachi/kodachi as the samurai's main swords. While there is no doubt tachis would still have been in service, most samurai would have katanas. I see no reason to believe that this would have been any different for cavalry.

[L'Ost]

So you have, for size : katana < tachi < nodachi ?

I always though tachi = nodachi.

[Panzercracker]

Eh. I don't entirely agree this assessment.

As you mentioned yourself, katana and tachi are nearly identical. While it is true that the transition from tachi to katana corresponds to the transition from mounted combat to infantry combat, it's not like there is any difficulty in using a katana from horseback. Once again, the swords are almost the same. By Sengoku, the daisho (katana/wakazashi) had replaced the tachi/kodachi as the samurai's main swords. While there is no doubt tachis would still have been in service, most samurai would have katanas. I see no reason to believe that this would have been any different for cavalry.

This side have interested infomation.
http://ejmas.com/tin/tinart_friday_0903.html
In history, Vietnamese soldier also use curved sword look like Japanese sword. In Vietnamese history records during 16th~18th century, Trịnh - Nguyễn war (they are Annamese warlords trade port in this Shogun 2), Japanese katana is short, hard to slash foot soldier from horseback, and easy to be broke if it take any direct hit, katana is not a sword for cavalry to use. And as foot soldier, katana is lack of heavy to make damage on iron armor (mainly use to stab or thrust), Vietnamese soldier use blunt or poleaxe weapon instead to deal those armoured soldier, but from 16th century, Vietnamese soldier use katana-like sword when they abadon heavy armor to step to gunpower warfare because katana is light and fast, it's mean katana is very good to deal light/non-armor soldier.

This is Vietnamese Cavalry sword during 15th century, but is replaced by Western-type saber during from 17th century.


Or in these draw, I don't think they carry katana

Spoiler Alert, click show to read: 

[Triumvere]

So you have, for size : katana < tachi < nodachi ?

I always though tachi = nodachi.

It's important to keep in mind that the tachi is, on average, only a tiny bit longer than a katana. And that there are "shorter tachi and longer katana" as someone noted above. There is not a big difference bwtween the two swords.

@Panzercracker

Those are definately tachi in the images, because of the way they are worn.

But, again, there isn't that much difference between a tachi and a katana. They are almost the same lenght with almost the same curvature - as is evidenced by the fact that the blades are difficult to tell apart w/o their original mountings. Both blades are short, which shouldn't be a big surprise as the medieval Japanese themselves were short. A tachi may be optimized for horseback use, and a katana for foot use, but that difference is small. Thus, if a katana is unusable from horseback, a tachi would be as well. We know that isn't the case.

[DeMolay]

Actually , i'm sorry but i don't agree with the post above although i don't claim to know better than others , just comparing what i know with what is posted by people sharing the same pasion as me

From what i've read most Tachis were not nearly identical to Katanas , it became so later on in the Edo Period for two reasons : 1) because many Tachi were remounted as katana and blades shortened for civil use 2) because the "fashion" in the Edo period was to come back to longer blade for katanas , the trend peaked in the 19th century although some regions resisted it

Tachi before the Edo period had 3 main characteristics that distinguished them from katana :

1) ornaments and rich Koshirae (furnitures )
2) much longer blade for cavalry use (up to 90-100 cm blade ) and usually much higher quality blade because tachis were destined to high ranked samurais most of the time
3) thinner blade and more pronounced Sori on the Tachi (for cavalry use ) compared to average katana of this particular period of time
4) balance of the blade is tip heavy for most tachis so you know immediately when you have a tachi in your hand if you 're experienced , whereas most katanas except Shobu Zukuri geometry and other rare designs of katana , had most of the weight near the base of the blade for greater agility and responsiveness whern fighting on foot , while Tachis were optimized for one handed use and the recurring movements of slashing on horseback


There were Some katanas with long blade before Edo period , but from what i know , during the Sengoku-Jidai , they were rather the exception than the rule , the majority as said by the article i posted and books i read , were short blades (2-10/2.20 shaku on average of blade length ) .

Since Kamakura until Sengoku-Jidai (when metal was rarer because of constant civil war lasting 1 century on the island and masses of ashigarus had to be also equipped with short swords ), the trend was to make short blades but thick enough to cut through most protection (if you look at Kamakura period katana , they were like 1.3kg , sometimes more and well thick blades, contrasting for instance with Edo period katanas with thinner , longer and lighter blades ) , and katana sori on average was not as pronounced as tachis , , because there was simply no need for it , the more sori , the less reach , and when blades are short and you're not on horseback , you don't want excessive sori , tachi had excessive sori to make it better for one hand use , assist the cutting (as tachi is one handed ) . besides i have never seen or read or heard about Samurais fighting on horseback with katanas , especially in Sengoku Period , it's clearly a historical innacuracy by CA .


The fashion of long blades on katanas (and long handle or tsuka) appeared in the period of peace ( espeically in the 19th century ) , from what i know for instance , before the Meiji restoration took place some battles between Imperialist and Loyalists (to the Shogunate ) forces , as far as i know , it's the only known occurence where Samurai have used long katanas on horseback as tachi were no longer crafted by that time

[Kraxis]

Obviously you know more about that subject than me.
The only reason I have read about the more pronounced curvature of Tachis and No-dachis is a result of the folding, the longer the blade the more curvature it would eventually recieve due to the limitations of the forging (don't ask me about the specifics, I did study mechanical engineering for a year, and did touch on the matter of forging, but nothing as complex as laminated metals, compounds or folding). Thus a shorter Katana would indeed end up with less degrees of curving, while No-dachi are wellknown to have almost impossible curves at times. But I suppose thicker blades would also tend to be less pronounced, but that would be in conflict with the tipheavy Tachi, as the greatest curvature would generally be at the last third of the blade.

The reason why Katanas would be downright impossible to use mounted is due to the way it was worn. Twist it up like a Tachi, and it would be classified as a Tachi, even if it would be a Katana per se. We are very rigid about the names, but this rigidity is either a modern invention (hey they used two names, one for cavalryswords another for infantryswords, that must mean two completely different weapons!) or one that was finally adhered to with finality in the Edo period, since the social and military structure became incredibly hard set. The way I have read it, it is the way the sword is used that determines it's name, rather than it's looks or differences.
Anyway, back to the point of wearing it. If you tried to draw a Katana in it's usual edge up style while mounted it would be decidedly arkward, if not downright dangerous to either man or horse. Just try and imagine your chair is a horse, then draw a fictive sword downwards. Either your arm can't stretch enough (due to the horse's neck), or you have to pull it's scabbard up... Basically it would be bad. Also, a shorter sword used while mounted has always been bad. There is a reason the Romans used the Spatha for their cavalry. Of course the difference between it and the Gladius is a lot more pronounced, but the basic idea is the same.

So Tachi Cavalry would be not just right, it would be the only way to name such a unit (though I would personally prefer Heavy Cavalry as that is their role, and no other unit fit that).

[Panzercracker]

It's important to keep in mind that the tachi is, on average, only a tiny bit longer than a katana. And that there are "shorter tachi and longer katana" as someone noted above. There is not a big difference bwtween the two swords.

@Panzercracker

Those are definately tachi in the images, because of the way they are worn.

But, again, there isn't that much difference between a tachi and a katana. They are almost the same lenght with almost the same curvature - as is evidenced by the fact that the blades are difficult to tell apart w/o their original mountings. Both blades are short, which shouldn't be a big surprise as the medieval Japanese themselves were short. A tachi may be optimized for horseback use, and a katana for foot use, but that difference is small. Thus, if a katana is unusable from horseback, a tachi would be as well. We know that isn't the case.

The weight and the lenght is the most important. The longer blade is easier to reach enemy foot soldier, the heavier is easier to slash armourd soldier and thicker make them harder to be take damaged -> less need to be repaired. As I said before in Vietnamese records when compare their Mã Tấu (Cavalry Sword) and katana, the katana don't meet requirement for hosreback use. And in the link I post above, said tachi and katana is the way to use, tachi is slash and chop while katana is thurst and stab (because their lenght and weight I said before). If you use thurst on horseback, why don't you use short spear?

[Triumvere]

The weight and the lenght is the most important. The longer blade is easier to reach enemy foot soldier, the heavier is easier to slash armourd soldier and thicker make them harder to be take damaged -> less need to be repaired. As I said before in Vietnamese records when compare their Mã Tấu (Cavalry Sword) and katana, the katana don't meet requirement for hosreback use. And in the link I post above, said tachi and katana is the way to use, tachi is slash and chop while katana is thurst and stab (because their lenght and weight I said before). If you use thurst on horseback, why don't you use short spear?

I'm having trouble here.

First we agree that tachi and katana blades are so similar that it is hard to tell them apart unmounted. Then you want us to believe that the katana is totally unsuitable to mounted combat, while the tachi is suitable? That doesn't make sense.

Furthermore, the katana is not a "thrust and stab" blade. While you *can* thrust with it (just as you can thrust with a tachi) it is not at all suited for that. The katana makes draw cuts.

Is the tachi superior for mounted combat? Sure. But we are talking about a really small difference here.

[Triumvere]

Actually , i'm sorry but i don't agree with the post above although i don't claim to know better than others , just comparing what i know with what is posted by people sharing the same pasion as me

From what i've read most Tachis were not nearly identical to Katanas , it became so later on in the Edo Period for two reasons : 1) because many Tachi were remounted as katana and blades shortened for civil use 2) because the "fashion" in the Edo period was to come back to longer blade for katanas , the trend peaked in the 19th century although some regions resisted it

Tachi before the Edo period had 3 main characteristics that distinguished them from katana :

1) ornaments and rich Koshirae (furnitures )
2) much longer blade for cavalry use (up to 90-100 cm blade ) and usually much higher quality blade because tachis were destined to high ranked samurais most of the time
3) thinner blade and more pronounced Sori on the Tachi (for cavalry use ) compared to average katana of this particular period of time
4) balance of the blade is tip heavy for most tachis so you know immediately when you have a tachi in your hand if you 're experienced , whereas most katanas except Shobu Zukuri geometry and other rare designs of katana , had most of the weight near the base of the blade for greater agility and responsiveness whern fighting on foot , while Tachis were optimized for one handed use and the recurring movements of slashing on horseback


There were Some katanas with long blade before Edo period , but from what i know , during the Sengoku-Jidai , they were rather the exception than the rule , the majority as said by the article i posted and books i read , were short blades (2-10/2.20 shaku on average of blade length ) .

Since Kamakura until Sengoku-Jidai (when metal was rarer because of constant civil war lasting 1 century on the island and masses of ashigarus had to be also equipped with short swords ), the trend was to make short blades but thick enough to cut through most protection (if you look at Kamakura period katana , they were like 1.3kg , sometimes more and well thick blades, contrasting for instance with Edo period katanas with thinner , longer and lighter blades ) , and katana sori on average was not as pronounced as tachis , , because there was simply no need for it , the more sori , the less reach , and when blades are short and you're not on horseback , you don't want excessive sori , tachi had excessive sori to make it better for one hand use , assist the cutting (as tachi is one handed ) . besides i have never seen or read or heard about Samurais fighting on horseback with katanas , especially in Sengoku Period , it's clearly a historical innacuracy by CA .


The fashion of long blades on katanas (and long handle or tsuka) appeared in the period of peace ( espeically in the 19th century ) , from what i know for instance , before the Meiji restoration took place some battles between Imperialist and Loyalists (to the Shogunate ) forces , as far as i know , it's the only known occurence where Samurai have used long katanas on horseback as tachi were no longer crafted by that time

Well, I guess I'll have to defer to your experince, then, since you seem to have more knowledge than I.

[jonny duck]

I'd read somewhere a while back (so not sure where to find the original source) but the tachi was the precursor to the katana, with the principle difference being that the tachi was worn blade down whereas the katana is worn blade up. The katana eventually superceded the tachi, progressivly from around 1200 or so. If anyone has any more info on whether that is true or not it would be a great help.

[Panzercracker]

I'm having trouble here.

First we agree that tachi and katana blades are so similar that it is hard to tell them apart unmounted. Then you want us to believe that the katana is totally unsuitable to mounted combat, while the tachi is suitable? That doesn't make sense.

Furthermore, the katana is not a "thrust and stab" blade. While you *can* thrust with it (just as you can thrust with a tachi) it is not at all suited for that. The katana makes draw cuts.

Is the tachi superior for mounted combat? Sure. But we are talking about a really small difference here.

Did my English is not good enought for you understand ? I'll explain 1 more: look again in my link
http://ejmas.com/tin/tinart_friday_0903.html
Dr. Karl Friday is Professor of Japanese History, University of Georgia, Athens, GA

"wakizashi no katana" ("sword thrust at one's side")

With very few exceptions, in literary and more prosaic sources alike, warriors are depicted using tachi to "cut" (kaku or kiru) or "strike" (utsu), while using their katana to "stab" (sasu) or "thrust" (tsuku).

Why katana is not suit for slash, especial when use on horseback? Vietnamese records also explain it. Becaus it is shorter than tachi, it's harder to slash foot enemy, and katana lack of thickness for make it lighter tachi. Result, easier to be broke or the edge will be serious damaged when take any direct hit on it or slash any hard objects like iron armor or other iron weapon, that why katana is very unsuitable for use on horseback. Summary, don't think you can use katana to slash like any films or game you saw, if not you will become familiar customer of blacksmith . You can ask some Japanese historian for Japanese record about katana is like in Vietnamese records or epic like in films, game v.v...

[Triumvere]

Did my English is not good enought for you understand ? I'll explain 1 more: look again in my link
http://ejmas.com/tin/tinart_friday_0903.html
Dr. Karl Friday is Professor of Japanese History, University of Georgia, Athens, GA

Your english is fine, but I am afraid you are misreading your link. Let me explain:

The tachi was a warrior's principal sidearm, employed when he ran out of arrows or was otherwise unable to bring his bow into play. Katana were used for grappling and other very close combat, as well as for removing the heads of slain opponents, and for committing suicide. Kondo Yoshikazu notes that these differing functions are clearly reflected in the vocabulary associated with the two types of swords: With very few exceptions, in literary and more prosaic sources alike, warriors are depicted using tachi to "cut" (kaku or kiru) or "strike" (utsu), while using their katana to "stab" (sasu) or "thrust" (tsuku).

Ok so far, right? But you've left out the most important part, which comes in the preceding paragraph:

In early medieval usage, single-edged long swords were most commonly called "tachi," written with any of several characters or compounds, while the term "katana" referred to what was later called a tanto or wakizashi--that is, a short blade worn thrust through one's belt. Companion swords of this sort were also known as "sayamaki" ("wound case") because of the wrapped design of their scabbards, or "koshi-gatana" ("hip sword") because of the way they were carried.

Two points:

1) The terminology has changed: the sword being called a "katana" in the early medieval period is NOT the sword we call "katana" today, but rather what we call a "tanto" (dagger) or "wakizashi" (short sword). Since shorter blades lend themselves toward thrusting and away from cutting, it is not at all surprising that they being used to "stab and thrust". BUT we are not talking about "katana" in the modern sense.

2) Note the time period: early medieval. We are talking primarily about Heian and Kamakura periods here - the time when the tachi was the dominant Japanese sword. The katana did not replace it as the principle sidearm until Sengoku, hundreds of years later. So this article is not particularly useful to understanding how tachi or katana were used in the time period of the game.

Why katana is not suit for slash, especial when use on horseback? Vietnamese records also explain it. Becaus it is shorter than tachi, it's harder to slash foot enemy, and katana lack of thickness for make it lighter tachi. Result, easier to be broke or the edge will be serious damaged when take any direct hit on it or slash any hard objects like iron armor or other iron weapon, that why katana is very unsuitable for use on horseback. Summary, don't think you can use katana to slash like any films or game you saw, if not you will become familiar customer of blacksmith . You can ask some Japanese historian for Japanese record about katana is like in Vietnamese records or epic like in films, game v.v...

Katana produced during sengoku vary widely in length, quality and thickness. It would be a mistake to assume that all of them were short, thin or of low quality. Furthermore, while poster DeMolay claims that sengoku tachi were 90-100 cm long, I have never heard such a thing before. I, however am not a swordsman or scholar of Japanese swords.

Let's see what DeMolay's link says:

http://wiki.samurai-archives.com/ind...281394-1595.29

Heian:

The shape of a Japanese sword ( Tachi ) in this age is Mihaba ( width ) near the Nakago is wider than that of near Kissaki, so to speak, like a man who standing with keeping his feet. Kissaki is small ( Ko-Kissaki ) and Sori ( curvature ) looks like suddenly fall to the ridge side at right above Nakago. But Sori near Monouchi is little. This shape is refined in a sense. Hawatari (length ) is about 75/80cm. This size is fit to chop the enemy on the ground with riding on Japanese horses. The horses in this age were not like present ones but small and massive. Moreover, it fit to stab the enemy on the ground because the curvature near the point is little and Nakago (tang) is short compared with the percentage of the blade. Hamon is Sugu, straight.

Nanbokucho:

As the footsoldier raised in importance once again, a very long sword, more suitable for this new horseback fighting style was created. This long Tachi was for driving away enemy, so the length was from 85cm to over 1m was made. Some of these Odachi or Nodachi or Odanbira arrived to a length of 120-150 cm. The longer ones were used by footsoldiers to cut horses legs and open gaps into enemy spearmen lines.

This need was another reason for the rise of the Uchigatana that became to be made in this period. The length is about 70 cm and it was used together with the longer Tachi. All blades followed the fashion to be gigantic as Tachi were. Tanto in this period have peculiar characteristic. The length is about 35cm and they were made by Hira-zukuri.

These too big blades all disappeared in a short period, soon after the end of the period.

Early Muromachi:

As the armies grew, the mounted soldiers became ever rarer, and the main force of armies consisted of foot soldiers. Even if many Tachi were still made, the time of the Katana was already dawning. Shorter blades were easier to carry and faster to draw. The centre of curvature of the blade moved to the center as the blades were increasingly designed for a fast draw and to be used on foot. Most swords were 69,7-72,7 cm in length and narrowed towards the point.

Late Muromachi:

Into the late Muromachi we find the artistic revolution of the Momoyama Era, when the Katana finally replaced the Tachi as main sword of the Samurai. The difference between a Tachi and a Katana is, to make an incredibly difficult thing the easiest possible, the position of the Mei (signature). The signature must be on the part of the blade that faces outside. So as Tachi is worn edge-down and Katana is worn edge-up, the signatures are placed in opposite positions. In absence of a signature the mounting is often the only difference between the two types of swords. Obviously this change was more a slow evolution rather then a sudden revolution. So we have a lot of blades that are "in between" that can't be easily put in a specific category.

Edo:

Katana (and Tachi) - to be 60cm or longer

So, the 75-80 cm is given as a practical length for fighting footsoldiers from horse back. According to wikipedia:

The length of the blade varied considerably during the course of its history. In the late 14th and early 15th centuries, katana blades tended to be between 70 to 73 cm (27.6 to 28.7 in) in length. While during the early 16th century, the average length was closer to 60 cm (23.6 in). By the late 16th century, the average length returned to approximately 73 cm (28.7 in).

... which would place the "average" katana close to that range. Given that most katana would be used on foot, we can expect the "average" katana to be optimized for such use... but that still leaves us the possibility that the larger katana - those above the average - were in the ideal length for mounted combat.

I've been all over Japan, and looked at a lot of swords. What I can tell you is that, those swords which were clearly identified as "tachi" has a slightly longer blade, with a slightly stronger curve, and a tapering toward the end compaired to those identified as "katana". Like I said previously, I am not a swordsmen or scholar of swords, and I have never held these swords nor can I say what period they were from. However, of the swords I saw there was not that dramatic a difference in their apperance. We can certainly assume that the "tachi" were optimized for cavalry use, but I think it would be a mistake to say that the difference between the swords is so great that the katana could not be used form horseback (or the tachi on foot). Remember, we are talking about optimization between to similar swords - so similar that it is hard for experts to tell them apart. We shouldn't exaggerate the difference.

Now, the caveat here is that many tachi were apparently cut down and tranformed into katana in the Edo period. This would help explain the ambiguity, and support the idea of the longer tachi being in wider use during the Sengoku period. Certainly we know that the Tachi was retained - at the very least - as a status symbol for ranking Samurai. One might postulate that such Samurai were more likely to retain their status as horseman as well - it has been noted that there was realatively little use of cavalry in the sengoku periods as opposed to infantry tactics. But the presence of tachi on the sengoku battlefield is not automatically a proof of cavarly use - many weapons would have been in use at that time, including older ones put into service (this includes the naginata, even though people on this board frequently imagine that no naginata were present on the battlefield.) Still, this is a good argument for the tachi being the primary cavalry sword.

Perhaps depictions of combat from the era might help us here. Are mounted samurai from the sengoku period generally depicted with their swords hung in tachi fashion?