It is used in BI, but can be used in RTW
BI:
short_pike, spear, spear_bonus_4
light_spear, spear_bonus_4
spear, spear_bonus_8
*Pike: Use shorter than normal spears. Can be used with phalanx ability or without it. The unit is still considered as infantry (and not spearmen).
Grants a bonus of 8 versus mounted units, but due to the qualities of the formation (spacing, cohesion, etc) it seems that it roughly gets an extra -1 versus everyone. It also seems that short_pike overrides light_spear and spear, so that when the two are combined
spear/light_spear is ignored, though due to it's own qualities it does slightly affect combat, depending on the units involved. Additionally, short_pike is required for units using the 'schiltrom' formation, because when in schiltrom and without short_pike, the soldiers will very rarely attack enemies.
- spear_bonus_x (BI only): 'x' may be any even number between 4 and 12 inclusive. Must be accompanied by spear or light_spear attributes, otherwise it has no effect. It stacks with the default bonuses of these two attributes.
- light_spear: Gives default bonus of +8 to defense vs cavalry, and penalty of -4 to defense vs. infantry. Offers less pushing power than spear.
- spear: Gives default bonus of +8 to attack vs cavalry, and penalty of -4 to attack vs. infantry. Offers more pushing power than light_spear. Units with "spear" attribute tend to lose cohesion and break lines (due to the extreme pushing power) with undesired results, so use is advised only with cohesive formations/attributes like short_pike, shield_wall, phalanx etc.
FATW:
light_spear, spear_bonus_4
light_spear, spear_bonus_6
light_spear, spear_bonus_6, short_pike
EDU Matic:
light_spear 4
light_spear 6 short_pike
spear 10 long_pike
MTW2:
light_spear, spear_bonus_4
spear, spear_bonus_8
spear, long_pike, spear_bonus_8
Aradan has tried to tidy it up, by giving us examples of balanced spear use in the EDU_matic. Because spear causes the unit to lose formation, it is replaced by light-spear in many cases. You can play around with the numbers, depending on your game, but for balance’s sake, I use the EDU-matic data as a guide.
Hope this helps?
Cheers
Phil