It's been some time since I played a Mongol campaign as the Japanese. I've only used ashi CBs to maintain troop parity on the strat map, tactical distraction and fodder. I'm not disputing their effectiveness when used as described; I just don't enjoy a game where ranged tactics dominate so much, particularly against a foe like the Mongols. But that's just me--I should use them, I just don't like them and it's not fun for me to play that way.

I try to contain the horde on Kyushu before their third landing. The campaign becomes much more manageable if this is achieved. I start building ports in Aki, Kawachi, and Hitachi immediately in order to establish rapid troop transport to the contested regions. I immediately start moving all available troops west except for a small group which I use to subdue rebellion in the far east (Echizen and Mutsu/Dewa iirc). The key points of resistance are Aki and the provinces surrounding it, Iyo on Shikoku with Awa and Kawachi (river provinces) as fall back defensive positions.

Any troops trained in Yamashiro receive an honor bonus--and it's the only province that can produce +3 Yari Samurai (eventually). Just don't forget to build enough cavalry units (in Yamashiro or Shinano for the honor bonus; you don't want to dilute your command units' honor level too much) to keep your command units at full strength--you don't want to lose your key taishos. If you use Shinano, remember that it's land-locked and you'll need a port in a neighboring province to deploy newly built cavalry quickly (same with Yamashiro, hence a port in Kawachi).

I find it important to engage with a high-honor taisho in command whenever possible. This bolsters morale for all troops sufficiently to maintain form in most situations, provided I attack as an army and remember that morale is always the primary weapon in a TW game. One of the major weaknesses of the invading army is that it lacks good leaders initially, and the nature/strength of its units lend to getting spread out (making the morale weapon easier to use, provided you have trained units that can deliver it, and can use them well on the field).

As most know, Mongol reinforcements are based on the value of the territories they conquered since their last reinforcements arrived (less expenditures on border watch towers and forts). If contained on Kyushu long enough, Japan's production kicks in and Japan's native might can be brought to bear. Restrict enemy reinforcements; increase the rate at which Japanese reinforcements are trained and deployed, etc., etc..

One thing I don't like about the campaign is that the landings seem scripted when it comes to where and when subsequent Mongol reinforcements arrive. After you've played a few campaigns, you can pretty much guess where they will land and when with reasonable accuracy. This makes it much easier to neutralize the landings, provided you haven't allowed them to take new provinces.

From a strategic point of view, obviously it's best to wipe them out before they get a foothold. This can be achieved in a few years (I've never won the opening Hizen battles ... has anyone else?)--before the third wave of reinforcements, but as Sasaki mentioned, this results in a fast, furious game using pretty much the units on the board at the beginning. It's tough, but not impossible.

To summarize the things I try to do: contain expansion (number of reinforcements), establish rapid troop transportation quickly ("sending" and "receiving" ports in smart places), establish the ability to train complimentary troops rapidly (usually one per type per turn, with one training center per troop type, two for spears and archers), organize into balanced armies, and use them well under good leadership on the field (tactics on the field--what makes STW so fun imo).

Heh: basically just play STW well, with a sound strategy and effective tactics. But if I'd just wrote that it'd be a pretty boring post.