The Tsingtao counterfactual begins in January-February 1939. Japanese doctrine, leadership, available ships, and political circumstances were still evolving and cannot be imported unchanged from 1941. The Kido Butai carrier concentration did not yet exist, and several ships central to the later Pacific War were unfinished. That timing changes both the Japanese options and the forces Britain could bring to the Far East.
Chapter · 0:30-1:33
Why a 1939 war would not follow the 1941 script
The opening premise is that Japanese naval doctrine changed markedly between 1939 and the Pacific War of 1941-45.