中国无敌

after b2 u are in a guessing game.

opp will either make a move which is faster than you, or do nothing.

wether it is bt4, or btd1, or bt, u/f+4 that they do, your ulp will always give you advantage.

if they do nothing, you will enter FC, again it become a guesing game, u get to do either ws+4_throw_f/c,d/f+3,4

all in all, it is good setup, but as andy say 4 is better choice.