The Taiwanese DVD covers for both movies directed by Yu Chien (https://hkmdb.com/db/people/view.mhtml?id=97384) that we have listed credit Yu Chien-chien instead: https://hkmdb.com/db/people/view.mhtml?id=11072

Considering that fact and the similar names and filmographies (Taiwanese DTV movies), I think they should be merged. I would also like to change the primary name from Yu Sin-sin to Yu Chien-chien. Any comments?

The merge and name change both seem reasonable to me! I think you're right that they're the same person.

@YangDe-shidi, thanks for the response!

Merged:
id 97384
Director (2 films)
Shao Nu Cheng Shu Shi (1995)
Sex Witness (1998)

into
id 11072
Director (4 films)
Chise Mengyan (1994)
Changing Partner (1995)
Those Who Are Undesirable Playmates (1995)
Club Girl's Love (1997)