KJF is a viable strat in my opinion. I’ve seen it work many times. The best way I’ve found to screw them over would be -
RUS- move 6 INF to BURI
Land 1 FIG in China
Uk - Buy 1 IC and 5 INF. - attack Borneo with 3 INF, FIG, Cruiser hit. AC takes out Trans. Attack New Guinea with 2 INF. Sub does whatever. Land Fig in China
If you win these fights which is entirely possible, Japan is already in a bind. US builds an IC to place in Sinkiang, an AC, trans and sub. Build pacific navy for two more rounds and move out by round 4. I have thought of counter attacking Pearl but I haven’t tried it yet.
Hope Russia can hold out, and for the first few rounds they can. UK buys only for the IC in India for rounds 2 and 3 and saves the rest to plop a navy down in round 3.
It is tricky, you just have to time it so the German stack on the Russian front isn’t big enough to take them down. As soon as the stop sending forces to the front have to concentrate on home defense, the game is almost yours.