Left: 其 (The image of a grain shovel/scoop (tool for threshing), that is used for throwing up the grain rhythmically in certain periods to separate the grain from the husk.), right: moon 月
Mnemonic
Grain scoops (at work) and the moon are only seen periodically.
The radical tsuki stands for moon or month when used at the right side of a character. However the radical niku 肉 that stands for body or body-part is in many cases simplified to 月 and thus looks equal as "moon".
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