tl;dr: There is enough ambiguity on Uesugi Kenshin's gender to allow many to make the conjecture that he may be female. In other words, Kenshin is either a fair-faced man who is extremely secure in his masculinity, or Kenshin was really a smokingly hot chick in disguise.
This would also make Takeda Shingen the biggest D-bag in the Sengoku era. You'll see why.
EDIT: Ugh. Wow. 3 AM again. I need to stop writing so late. If you find any errors, I'll probably fix it in the morning.
WARNING: WHILE EVEN I ADMIT THAT MOST OF THIS IS CONJECTURE AND NOT MEANT TO BE TAKEN SERIOUSLY, I HAVE COBBLED TOGETHER ENOUGH EVIDENCE IN THE FORM OF HISTORICAL FACT AND OBSERVATIONS TO MAKE THE ARGUMENT VIABLE. ONCE THIS PIECE IS READ, YOU CANNOT UNSEE IT. I ADVISE THAT YOU LEAVE WHILE YOU STILL CAN.
I AM NOT RESPONSIBLE FOR ANY ALTERATION OF YOUR IMAGE OF KENSHIN.
THIS IS YOUR LAST WARNING.
Alright. Let's begin.
Let's talk Uesugi Kenshin. I don't really need to say much about him, but he was a very interesting individual - certainly, one of the few true idealists in this era. He fought for what he perceived to be right, and had little desire to actually expand his territory - part of the reason why he basically hung around Echigo and didn't do anything else. Out of the sixty-some battles he participated in, however, not a single one was unwarranted. Kenshin was basically a peerless commander, but he also lead from the frontlines - for more examples, check out my writing on Kawanakajima, also posted on this forum.
Nonetheless, what we have is interesting. Kenshin, interestingly, had no children. His two sons were adopted. This alone may not be anything particularly significant - after all, Hideyoshi was pretty much infertile. However, there were many whispers - some suggested that Kenshin was simply asexual, or impotent, or that he preferred the company of men. Because Kenshin was somewhat introverted and not prone to expressions of grandiosity like the other daimyos, we have comparatively fewer resources.
Still some others whisper that the God of War was really a woman. This was, in fact, so popular a rumor that it lasted to today, and you can find female Uesugi Kenshins in everything ranging from Nobunaga's Ambition to Sengoku Rance. Interestingly, a recent poll in Japanese high schools show that many (more than 40% less than 80%) students believe that Kenshin was female, or that his gender was in dispute.
For the purpose of this post, I'll be citing a popular piece written by contemporary novelist/historian Yagiri Tomeo. While he is discredited in academic circles for having extremely derpworthy ideas (re: Mitsuhide and Nobunaga was really in on Honnoji, for instance), his composition on Uesugi Kenshin is interesting. I will be also adding my own analysis and conjecture based on personal research, and let you, dear reader, decide on what is true and what is fiction.
You can still back out if you can.
First, for first-hand sources. In various books of poetry recorded in the latter Sengoku/Edo period, songs are suggestive of Kenshin being "more than a man." However, ignoring folk-tales and songs, we have the Toudaiki (当代记), composed by one Matsudaira Tadaaki. This is arguably one of the most reliable first-hand sources we have on the Sengoku era. Toudaiki is composed in the very early Edo period, and serves as a first-hand account of many historical details. Of particular interest is this entry, which tells us about the manner of Uesugi Kenshin's death.
Note the term 大虫. You may think that this means tiger, but in reality, given the historical context, this type of disease refers to a very specific illness: a type of uterine bleeding. A bit unusual, don't you think? Men clearly cannot die from it, at any rate.
Those who may be questioning Matsudiara, I'm gonna toss this out here now. He was known to be a man who was knowledgeable in medicine. There's about as much chance of him getting this one messed up as say, you or I stop breathing. Furthermore, why would he lie about such a thing when every single other detail in his book is more or less right on the dot?
Either Matsudiara was the best troll in Japanese history, or he knew something that we didn't.
There are other sources also documenting the same thing - that Kenshin died of certain diseases that's specific to us girls. Some suggest cervical cancer, others cervicitis, but most tend to agree with this bleeding thing. What is more interesting is that in most other sources, Kenshin's manner of death is never described - the Dragon of Echigo simply died.
Still skeptical? Let's turn to other historical sources. In all sources - check the MHNE, Hojo's archives, Koyo Gunkan, whatever. You will quickly find out something interesting: Uesugi Kenshin has severe stomach cramps and pains around the 10th of every month. The pains are so severe, in fact, that he is unable to ride into battle. His entire battle schedule is more or less scheduled around this event.
What does this sound like?
I'll give you a hint. It's something we go through every month.
Still not convinced? Let's take Kenshin's campaign against the Hojo (the one that eventually lead to the siege of Odawara), for example. In the Matsudiaraki, along with Hojo's own archives, it is recorded that on June 11th, due to stomach pains, Uesugi Kenshin was forced to retreat despite the fact that the Hojo were pretty much broken on the field of battle. In other words, he could have had that castle if he attacked -
Oh, let's take a look at when Kenshin died. In general, historians agree that it was either March 9th, or March 11th.
You beginning to see a pattern here?
"But Ying, we know what Uesugi Kenshin looks like. He clearly has a beard!"
Aha. Here's where the interesting thing comes in. Compare portraits and paintings of Kenshin in the Sengoku era versus the portraits in the Edo era. You will quickly notice that the beardy, gruff looking Kenshins all come from the Edo era. Self-portraits of daimyos are comparatively common - for example, Shingen likes to put crimson lotus fires around himself. Oda likes to demonize himself, etc.
Kenshin's self-portrait that was period appropriate (i.e. pre-Edo) not only depict Uesugi Kenshin as a beardless, clear-faced man of relative youth, but the art style is deceivingly feminine.
What's more, many self-portraits of Kenshin portray him as Bishamonten, standing above a cloud. Some of the oldest ones are still surviving today in Rensenji if you want to see it. Anyways, the Bishamonten thing isn't unusual, but what is unusual is that a crimson colored cup is placed beneath Bishamonten's feet. Now, here's what's interesting. In the Kourou Monogatari (an old, old historical source), it talks quite a bit of symbolism in ancient art. In particular, the vase or bottle was used to symbolize men, while cups are used to symbolize women.
...Hm. Kenshin clearly understood the symbolism - he was very well learned and was an accomplished poet, musician, and writer. So why would Uesugi Kenshin draw a cup in his own portrait? Some say that it is Kenshin's favorite object, but perhaps there may be something more to the tale than just favoritism...
But that's not all. In the temple to Bishamonten (well, technically, Kukurihime)in Kasugayama (Kenshin's home castle), Bishamonten is for some reason, female. Instead of the typical manly hammer man we see in a lot of temples, a rather imposing looking female is present with the banner Bi. I actually visited this place once, and the abbot explained that the statue was there since Kenshin's time - they had no idea why it was female either, but they keep it there because they've kept it for all generations.
Worth mentioning that in general, the temple have a pair of statues - one male and female. Only this particular one in Echigo has a single female statue.
Could the symbolism and the images be Kenshin's way of secretly communicating to us?
"Well, that's easy! All we have to do is do some DNA testing. We have modern science now - didn't we do Masamune earlier?"
Actually... You know, you're not the only one who came up with that idea. Unfortunately, that isn't possible. Kenshin's remains is a closely guarded secret - they've even got the guts to stand up to the Shogunate when information was requested. What was more interesting, perhaps, is that when the Uesugi was forced to relocate, they always took Kenshin's remains with them to their new fief. Interestingly, only Kenshin's remains were taken - the other family members and ancestors were left as is.
So... This is clearly not a case of ancestor veneration. In fact, this was a great shamefur dispray. The burial sites of their ancestors is basically what kept the Sanada herpaderping around Matsushiro. The remains of your clan's ancestors are sacred, and moving it is akin to graverobbing. Furthermore, Kenshin himself left no special request telling his descendents that they must lug him around, for whatever reason.
So what did the Uesugi have to hide?
... See, if Kenshin was female, the Tokugawa Shogunate could invoke the ruler's edict. A clan must formally have a male head as ruler, or else they risk having their lands divided up by the Shogun. This was a part of several legislation expanded upon during the Tokugawa Shogunate's early rein to curb the influences of potentially rebellious daimyos.
Do you see my point? We have no conclusive evidence, but the case for Uesugi Kenshin being female is not a bad one. Female rulers were not common, but they were by no means uncommon - there are numerous women fulfilling a leadership position in times of urgency, or when the opportunity presents itself. Before we can do that, however, we should probably look at some anecdotal evidence, just so that we get a better idea of what Kenshin's like.
So, first things first. In almost all cases historically, his appearance was described as "beautiful." I unfortunately have NO IDEA how to type that particular kanji, but I can explain a bit about the context. It's not "pretty," it's not "handsome," it's basically drop-dead gorgeous - the term, for comparative purposes, is often used to describe goddesses. See, if I was a dude at the time, I'd be upset if someone used that to describe me. It's just something unusual, but Kenshin seemed to have been fine with it.
Let's see... His height is somewhat contradictory. Some describe him as imposingly tall, and some as ridiculously short. In fact, most do tend to put Kenshin on the tall side - in Uesugi's own family records and through analysis of armor, we deduce that his height was about 158cm. That's not tall by anyone's standard - but it would be tall for a woman, especially for that time.
(For the record. I'm about 175cm, or 5'10. If I was in the Sengoku era I'd be a giant, essentially. )
Other odd bits. We know that he likes poetry. He also likes to read really, really trite love stories. Kenshin was a huge fan of the Tale of Genji and other tales dealing with romance. At the time, this is a book that no self-respecting manly daimyo would DARE be caught with - it had NOTHING to do with Bushido! It'll be, I dunno, like Schwarzenegger reading Twilight or something.
Perhaps it was due to his choice of reading material, Kenshin's writing and speeches are also feminine in nature. It's hard to explain stylistically, but for example: whereas Shingen would list off heroics and promises of great sacrifice to the Gods if he was given victory, Kenshin's writing basically boiled down to: we need to win, therefore, please let us win. The tone is very feminine, and the rationale and reasoning was unconventional at best, and downright emotionally laden at worst. Also. Here's what his writing looked like.
(Image taken from Nigata Prefecture Museum of History)
Go compare this to, I dunno, Takeda Shingen, and you'll be raising eyebrows too.
Other tidbits... Well, he was known for his ability to drink. Except, we know that Kenshin doesn't go beyond three bowls. Again, context-wise, makes more sense if Kenshin was female, because three huge things of sake IS pretty hefty.
Other than that ... when he went up to Kyoto, none of the female officials and the royal consorts really paid much attention to him. This is, I think, one of the most hilarious counterarguments for "Kenshin is gay." You'd think that even if he was a bit effeminate or whatever there would be plenty of girls swooning over him, or at least find him to be fascinating. But no. He was mostly ignored.
... This might be a bit biased, but I can tell if it's another girl dressing up as a man pretty well. I know personal experience isn't a good argument at all, but I'm gonna bet that the girls (those who were straight, anyways) at court weren't stupid either.
Uesugi Kenshin got along with women very, very well. In fact, for that matter, it is recorded that he basically had free access to the female's quarters and he hung out with the Ashikaga shogun's mom and sister quite a lot. Historically, only other women were allowed in the female's quarters. This is another bit that's puzzling - no matter how close Kenshin was with the Shogun, allowing a man to mingling with the females of the household was a bit out of character, don't you think?
So, in light of all this. What can we conclude? The answer is: nothing. Nothing here is conclusive - everything can have a counterargument to it, and there are many, Japanese and otherwise, who will JUMP on me for suggesting such a thing.
... But it is interesting, isn't it? To think the God of War a woman? Can you imagine how brave she would have been? Silently enduring through a world torn apart by war and chaos, fighting stubbornly for only what she believed to be right. We would never know why she never married - perhaps she didn't want to lose control of Echigo, knowing that she was its only hope against the likes of the Takeda, Hojo, or Mogami. Perhaps she had her heart broken at some point in her maidenhood, or perhaps she did have someone she had her sights on - but because of her unique status in the Nagao-Uesugi clan, there was no way that relationship could have been consummated anyways.
Whatever the case may have been, she fought on for Echigo. Her retainers almost certainly knew the truth. If Uesugi Kenshin was indeed female, then perhaps the best evidence supporting her comes not from the historical sources that was recorded, but rather from the multitude of rebellions in her land. Some, like the Usami or Naoe, may have been impressed by her strength of will. For she - if he indeed was a she - breathed a fresh gust of idealism in the Sengoku era. Others, of course, wouldn't have stood by having been ruled by a woman. Rebellion was the only way.
Would Kenshin have understood their biases? We would never know. Would we know if Kenshin was a he or a she? We don't know. Someone may have known. Naoe Kanetsugu, who supposedly completed Kenshin's portrait, would have certainly known. Did they care? Probably not. Did the other daimyo care? Again, probably not. Maybe it was an unspoken thing, or maybe it wasn't.
Who else knew? Maybe Takeda Shingen. If Kenshin was indeed a woman, then the date for Kawanakajima couldn't have been picked better: it was again, around the 10th or the 11th.
... If this is the case, then, it makes the dynasty-warrioresque charge by Kenshin all the more impressive. I cannot imagine moving at all with those cramps, much less actually going in to fight. Nonetheless, we know that Shingen respected Kenshin very much. Did Shingen know something that we didn't? We won't know that either.
Did Oda know? Tokugawa Ieyasu? Hojo Ujiyasu? Maybe to the former, and probable to the latter. When the Uesugi was reassigned after the Segikahara, why didn't Ieyasu press the issue about Kenshin's legitimacy? Was it out of respect for an old rival up north? We don't know.
We'll probably never know.
History is interesting, isn't it? There is so much you could do with it. There is so much we know, and yet, at the same time, so much we don't know. In the end, however, history is what we make it out to be. So now you know a little more about what I know - what others knew.
And you will subconsciously influence and shape that into something that is unique to you.
Just who was Uesugi Kenshin?
I don't know.
If my little piece has made you think, made you contemplate what was previously thought to be foolish or unthinkable, then I think I can call it a job well done.
Thank you so much for reading. I know my writing is long, and quite dry at times, but like all of us here, we're all slowly improving.