https://en.wikipedia.org/wiki/JIS_X_0208#Kanji_from_unknown_...
Due to this thorough investigation, the committee was able to pare down the number of kanji for which the source cannot be confidently explained to twelve, shown on the adjacent table. Of these, it is conjectured that several glyphs came about due to copying errors. In particular, 妛 was probably created when printers tried to create 𡚴 by cutting and pasting 山 and 女 together. A shadow from that process was misinterpreted as a line, resulting in 妛 (a picture of this can be found in the Jōyō kanji jiten).