Apparently randomly, Mayuzumi selected 52–72 men (accounts vary), and ordered them shot on the fantail after they refused the honor of death by sword, and pitched the bodies into the Indian Ocean.
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After his promotion to lieutenant on 1 December 1919, he was assigned to the Tenryū, served a year as communications officer on Chichijima in the Ogasawara Islands, and returned to serve as communications officer on Mutsu, and seaplane tender Wakamiya.