flag
旛 centers on a flag: a piece of cloth used as a symbol or signal.
旛 combines 方 (flag) with 番, which likely contributes the sound. The character is used for a type of flag or banner.
The left side 方 suggests a flag, and the right side 番 (number) can be imagined as a numbered flag used for signaling.
For ヘン, picture a hen sitting on a flagpole: hen -> ヘン, and the flag flutters above.