The Briton was one of five drivers, including Brawn team mate and closest title rival Rubens Barrichello [ Images ], to be punished for speeding in Saturday's crash-strewn qualifying while yellow warning flags were being waved.
Button can only win the championship on Sunday, with two races to spare, if he scores five points more than Brazilian Barrichello.
That looked unlikely as night fell at Suzuka, with the stewards announcing the starting grid demotions after deliberating for more than three hours.
Button, who needs to finish at least fourth if the title race is not to go on to Brazil [ Images ] in two weeks' time, will now start 12th on the provisional grid with Barrichello ninth.
Red Bull's Sebastien Vettel, the only other contender for the title, will be on pole position alongside Toyota's [ Images ] Italian Jarno Trulli [ Images ] after a chaotic session that had to be stopped three times due to crashes.
Britain's outgoing world champion Lewis Hamilton [ Images ] will line up third with BMW-Sauber's Nick Heidfeld [ Images ] alongside after Force India's [ Images ] Adrian Sutil [ Images ] was dropped five places from fourth.
Buemi, who scattered debris across the track and brought out the warning flags when he skidded along the barriers in the second part of qualifying, was also reprimanded for impeding others and posing a potential hazard by staying on the track.
The final grid positions were further muddled by uncertainty over Toyota's Timo Glock [ Images ], who crashed heavily and was taken to hospital. If he does start, it will be from the pit lane since he will need a new chassis.
A spokeswoman for the International Automobile Federation said the grid would not be published before Sunday.
McLaren [ Images ] also changed the gearbox on Heikki Kovalainen's [ Images ] car, dropping the Finn five places from ninth originally. Force India's Tonio Liuzzi, who qualified 19th, also collected a similar penalty but actually moved up to 18th place due to Glock's demotion.