Uchi benkei is a Japanese word that means people who are bossy at home but submissive outside. So, selective mutism may be an extreme form of uchi benkei (Many children with selective mutism are not so bossy at home, though).
Some Japanese people use a slang net benkei. Net benkei is people who are bossy on the Internet but submissive in the real world.
What is benkei ? Benkei is a warrior monk in 12th century. He served Minamoto no Yoshitsune, a leading general. He was a brave warrior, so people today use the word benkei as an analogy for bossy people.
Saito MusashibÅ Benkei (Wikipedia)
Minamoto no Yoshitsune (Wikipedia)
Index of SM in Japan
