A limited future-warhead counterfactual for Japan in 1941

Would a small supply of future nuclear warheads allow Japan to win the war in 1941?

The assessment is that it could lengthen the war but would not provide enough capacity to secure victory.

The scenario gives Japan a small number of future nuclear warheads in 1941. Their use is expected to lengthen the war by damaging major industrial or political centres. The assessment nevertheless rejects a Japanese victory from such a limited supply. The warhead quantity remains uncertain.