暗算
あんざん · anzan · JLPT N1 · noun
arithmetic
🧠🔢 暗 = dark/hidden + 算 = calculate: calculating in your head, out of sight, with no paper or device
The first character 暗 means dark or hidden, and 算 means to count or calculate. Together they name arithmetic done silently inside your head, with no pencil, paper, or calculator.
暗 — sun 日 + sound 音 (phonetic)
暗 is a semantic-phonetic compound. The 日 (sun) component carries the meaning, suggesting absence of sunlight, while 音 (yīn, sound) provides the phonetic clue for the reading àn. Originally meaning 'dark' or 'dim,' it later extended to figurative senses like 'hidden' or 'secret.'
算 — bamboo 竹 + abacus 具 (eye 目 + two hands 廾)
Originally depicted counting with bamboo rods on an abacus-like device. The top 竹 (bamboo) refers to the bamboo counting sticks used in ancient Chinese arithmetic, while the bottom shows hands manipulating them. The meaning broadened from 'to count' to 'to calculate' or 'to plan'.