The second film of the Harry Potter series opened throughout Japan on Saturday at about 860 screens at 360 theaters.
It was the largest opening ever for a movie in Japan.
Nearly 400 people lined up at a theater in Tokyo's Yurakucho district to get into a 7:30 a.m. screening of "Harry Potter and the Chamber of Secrets."
Some movie houses were so packed people had to stand.
"Chamber," based on British author J.K. Rowling's best-selling book, is the sequel to last year's smash hit, "Harry Potter and the Sorcerer's Stone."
The first film made a record 1.5 billion yen in the first two days of its Japan release. Its distributor, Warner Bros. Pictures, hopes to set a new record this weekend with the sequel.
"Sorcerer's Stone" grossed $970 million worldwide.