mochi added to rice gruel on the 15th of the first month
Rare seasonal term referring to a custom of adding mochi to rice gruel on the 15th day of the first lunar month (around the time of the New Year).
The word 粥柱 refers to the custom of eating rice gruel with mochi added on the 15th day of the New Year.
Compound of 粥 (kayu, 'rice gruel') and 柱 (hashira, 'pillar'), possibly from the idea of mochi pieces standing like pillars in the gruel. The exact derivation is uncertain.