Is this a trivia item or do you just want to know? His agent recommended him to audition because it portrayed Asians in a positive light. After refusing he auditioned and was called back and got the part that way. Plus back then mot too many celebrities were excited to do a video game film after all the disastrous ones by that time, so Robin had it easy anyway. Here's an interview where you can get the info in his own words: https://movieweb.com/mortal-kombat-robin-shou-passing-liu-kang/

I just wanted to know. I also wondered how Cary Hiroyuki Tagawa got picked to play Shang Tsung.