upside-V-shaped gong
磬 centers on a specific ancient percussion instrument: an upside-V-shaped stone gong used in traditional music.
磬 combines 殸 (a phonetic component associated with sound or striking) with 石 (stone), reflecting the instrument's material and function as a stone gong.
The top part 殸 suggests a striking action, and the bottom 石 is stone. Picture a stone slab shaped like an upside-down V being struck to produce a resonant gong sound.
For ケイ, imagine a stone gong shaped like the letter K: K -> ケイ, and when struck it rings out with a clear 'kay' sound.
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