Were these weapons always used in pairs ? I know, when you see them in Wing Chun, there are two. I compare them with the Japanese sai (but hudiedao are sharp !).
But there is a Japanese weapon called a 'jutte'. Mostly a simple iron bar with 1 hook. A weapon also used for parrying and this weapon was used alone.
Just a thought...could certain types of hudiedao be used in the same way ?