In an ATL, in 1920s and 1930s when the SU were already entrenched in power, IJ would better off trading with the SU in the open while sending "volunteers" to Finland or Estonia to help fight the Winter War, with reference to Franco's Spanish diplomatic stance. However, if the USA did not interfere in around 1925 as in the OTL to force Japan, IJ could still retain the whole Sakhalin island. Then IJ could get the another two-thirds of the 470,000 tonnes. German technological help could turn unused timber from paper marking and/or coal to oil and there would be an unestimated albeit meager amount of oil for use. So in a nutshell, IJ in 1930s either traded with the the USA, the SU or the Netherlands for oil in the Dutch East Indies...