Conversion to Christianity?

[Togakure]

One great thing about converting early is early access to the morale penalty inflicted by firearms. In STW, morale matters, and even the lowly arquebus can be quite useful, particularly when coordinated with other morale attacks like flanking, cavalry charges, monk attacks, archery fire, assassination of a high-honor general on the field, etc.. The arq suffers in range and is more sensitive to moisture, but it's more powerful, and bottom line: still inflicts the morale penalty. If I go the Christian route, I'll usually have 1-2 units in an "ideal" 16-unit stack. If conditions permit, they can contribute much to routing the enemy and winning the battle.

Edit: on the subject of Warrior Monks, many times I have gone Christian in mid-game while controlling provinces with Buddhist Temples, producing monks, without incident. I just stationed a larger ashigaru and shinobi garrison in the province with the temple, and perhaps an extra ashi and/or spy in neighboring provinces that are known to be rebellious (those surrounding Kaga, Kii etc.). Best of both worlds.