Conversation so far:
What did Donnie Yen do with martial arts?
Donnie Yen Ji-dan is a Hong Kong actor, martial artist, film director, producer, action choreographer, stuntman and multiple-time world wushu tournament champion.
When did Donnie Yen start learning martial arts?
At a young age, under the influence of his mother, Donnie Yen developed an interest in martial arts and began experimenting. Yen then started kung fu when he was nine
Did anyone else teach Donnie Yen?
Donnie Yen's parents, concerned he was spending too much time in Boston's Combat Zone, sent him to Beijing on a two-year training program with the Beijing Wushu Team.

Question: How long did he train there?
Self-contained rewrite: How long did Donnie Yen train in Beijing?