無患子 むくろじ
mukuroji

Noun

1. Indian soapberry (Sapindus mukorossi); Chinese soapberry; washnut; soapnut tree

Usually Written in Kana
羽子板 はごいた はね たまは「むくろじ」という大木 たいぼく たねです。
hagoitade tsuku haneno tamawa"mukuroji"to iu taibokuno shudesu
The feathered balls you hit with a battledore are the seeds of a large tree called 'soapberry'.