early-maturing rice
稙 centers on rice that matures early, specifically a variety planted and harvested ahead of the main crop.
稙 combines 禾 (grain/rice plant) with 直, which likely contributes the sound and may relate to the idea of something direct or straight, possibly referring to a straight-growing early rice variety. The exact historical development is uncertain.
The grain radical 禾 beside 直 suggests rice that grows straight and direct, maturing early without delay.
For ショク, imagine an early rice harvest that comes as a shock because it is ready so soon: shock -> ショク, and the rice is already mature.
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