The legend says one can ride a wooden raft up to the Milky Way.
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槎 is a literary word for a wood-or-bamboo raft (and a verb 'to hack trees'). It is largely replaced by 筏 in modern Chinese and rarely stands alone. It is famous from the poetic image of riding a raft 槎 up to the stars. Built on the wood radical 木.
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Literary and archaic. 槎 appears in classical poetry, not in everyday speech.
