Shinzo Abe poses inside the cockpit of a T-4 training jet. The photograph sparked uproar   in South Korea and China as the number 731 reminded  many of the infamous Japanese bio-warfare Unit 731, which carried out experiments on live prisoners and unleashed a plague on Chinese civilians.  Photograph:  Reuters
Letter from Tokyo

Japanese leaders rarely pose anywhere near army hardware, part of the country’s postwar taboo on overt displays of militarism. So when a grinni(...)