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umeboshi; pickled dried ume; pickled dried plum
おにぎりの具には梅干が一番合うと思う。
I think pickled plum goes best as a rice ball filling.
祖母は毎年庭の梅で梅干を漬ける。
My grandmother pickles umeboshi every year using plums from the garden.
弁当箱の真ん中に梅干がひとつ置かれていた。
A single pickled plum sat in the center of the lunchbox.