dual pronoun, I, you and me, we two
昝 centers on a dual first-person pronoun: it refers to 'I' and 'you' together, meaning 'we two' or 'you and me'.
昝 combines 处 (place) and 日 (sun/day), but the exact historical development of this character as a dual pronoun is uncertain. It may have been a phonetic loan or a regional variant.
The top 处 suggests a place, and the bottom 日 suggests a day. Imagine two people sharing the same place and day, becoming 'we two'.
For サン, picture the sun (サン) shining on two people together: sun -> サン, and the sun unites 'you and me'.
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