Japan flaunts her air power ; Flies 75 war planes to Manchukuo to "show" Russia ; by associated press. Tokyo, Sept. 20 -- To the new kingdom of Manchukuo, quarreling with soviet Russia over boundary questions, Japan today gave an impressive demonstration of her military might. Seventy-eight battle planes successfully crossed the 450 miles lying between Darien, in southern Manchukuo, and Hsinking, Manchukuan capital, dispatches to the newspaper Asahi here reported, while Japan's combined war fleet continued maneuvers off Darien. Purpose of the mass flight ostensibly was to felicitate Emperor Pu-Yi of Manchukuo on his coronation last March 1. It came hard on the heels, however, of Hsinking's formal protest to Moscow against alleged Russian occupation of an island at the junction of the Amur and Ussuri rivers, territory which Manchukuo claims. The Russians, ousting Manchukuans, set to work digging trenches, it was asserted.