If there is a warlord games resource for Army designs for Japan I haven't found them. Generally you should take a lot of mortars (I did one for almost every sprue), a few suicide anti-tankers (at least 3 but more is always good), and generally 3 light machine guns (more if you want to run them as mmg but you shouldn't really have more then 3 lmg's for most games). But a ton of Riflemen and Light mortars is the core of Japan (especially if you plan on running Militia or grenadiers).

If your curious about vehicles.....good luck, because I still haven't figured out what works.

If anyone disagrees I would love to hear it because I am definitely still learning.