Na Nga-shu has only one credit - in Love in blue
This movie stars Ma Ya-Shu (???) - her Chinese name is similar to Na Nga-shu (???)
There are no credits for leading actors in the movie itself, and also no Na Nga-shu's name in the ending credits, and the VCD cover lists all the credited in our DB actors (in Chinese) except Na Nga-shu (and except Fung Chit, whom I identified today).
I suspect that Na Nga-shu (???) is just a typing mistake of Ma Yu-shu's Chinese name, and suggest to delete Na Nga-shu from DB.