Originated as a nucellar seedling of Miyagawa Wase, recovered from a controlled pollination experiment involving Poncirus trifoliata at the Okitsu Horticultural Research Station (1940). It was registered in 1963. Sibling to "Okitsu Wase". Although genetically maternal, it differs from Miyagawa through stable physiological mutation, showing earlier maturity, reduced flowering intensity, and improved sugar accumulation. Fruit somewhat more oblate than Miyagawa, but higher in sugar, usually lower in acid; and earlier in maturity.