当時
とうじ · touji · JLPT N3 · noun
time
🕰️ 当時 = that very (当) + time (時): that time back then
当 means the one in question, as in 当日 (that day). Add 時 (time) and you get the time being talked about, i.e. back then. It sounds like toe-gee, and that is the reading とうじ.
当 — small ⺌ + crown 冖 + hand 彐 (simplified from 當: 尚 + 田)
Originally written 當, combining 田 'field' with 尚 as a phonetic. The early sense was 'to match' or 'face' a field of equal value, extended to 'correspond to', 'ought to', and 'serve as'. The simplified form 当 streamlines the upper 尚 component.