In 1939 Japan realized it underestimated China’s resistance — FSB archive
Disclaimer: TASS is Russian government propaganda, and not a reliable news source.
According to Friedrich Schildknecht, on one day after their arrival in Tokyo in late May 1939, Germany’s deputy military attache in Japan, Lieutenant-Colonel Erwin Scholl (the German military attache was at the Chinese theater of operations at that moment) invited them to dinner at Imperial Hotel