Some of the kanji (japanese traditional characters) seem to indicate Jizo and Mizuko, literally "water child" which can mean 'dead foetus'. This shrine is probably dedicated to children lost to miscarriage, as there is for them a ceremony called Mizuko kuyō ('fetus memorial service'). In Japanese folklore, Jizo hides the children in his robes to protect them from demons and guide them to salvation. They are very popular in Japan. Interestingly, Jizos can also be translated by 'Womb of the Earth'