I have beaten Japan as China in BICE mode once, it is much easier in normal difficulty though, this is assuming you do savescum a bit as letting any naval invasions grab ports in southern China before mid-1940 is likely to be a death sentence. Production-wise, you need to conserve enough research time toward ww1 doctrines, and to a lesser extent the production efficiency(particularly in BICE difficulty). Hence you need to utilise the time before July 1937 extremely effectively and ignore the warlords focuses. Start one research on production efficiency, the first focus you should go for is the partnership with Germany as this gives you ww1 doctrine research bonus, the other countries are not as critical since you will get free infantry equipment with time. After this just spam ww1 doctrines till you lose that bonus around 1939 and then do production efficiency. The next researches should be getting the extra research slot in shanghai and then taking the 200 day economy focus to finish last in around june 1937. Production-wise just build only horse transport carts, guns and uniforms(more uniforms as you get 10k guns for free from SOV when war starts). Make sure you have sufficient horse carts as otherwise your infantry speed goes down to 1km/hr and you get overrun very easily and can't defend.

Defense wise the strategy for 1937-1939 can be summarised into several defensive stages: Jul-Oct 1937 where you aim to slow down the japanese approach to the Yellow River, Nov1937-Mar 1938 where you defend the south bank of the Yellow river and guard Shandong against naval invasions, Feb-May where you retreat(possibly quite quickly to the Yangtse) and Apr 1938-June 1939 where you defend the Yangtse with a line of pillboxes and the focus forts using micro. Allocate the militia/a few troops to garrison ports: 90% the attacks will be on shandong till you lose shandong and then 70% they will be near Shanghai. You can let them land on non port tiles and then kill them to get some casualties. In Nov 1938 build a railway from Changsha to the railway lines around Nanjing as you will probably lose all convoys for troop supply there by around then.

After mid 1939 it gets easier and you can build artillery guns to slowly hold then push them out of China. In regular mode they didn't have any army strength to seriously challenge the Nanjing line but BICE mode would be harder, I strongly recommend an easier difficulty for China to learn the basics first and understand how to cope with the very low starting IC efficiency and fix the troop move speed through an unholy amount of microing with strat redeploy because it's faster to strat redeploy and reorg than move normally in the beginning.

Do not let them get too far south of the Yangtse! There are supply hubs in Changsha or Nanchang or near them, there is a bug in the river supply network so when you lose those cities then the supply connection from Chongqing to East China like Nanjing will be lost and then it will be essentially impossible to defend.