Tokyo's Nikkei average sank 0.98 percent today as growing concerns over a vote on bills to privatize Japan's postal system encouraged investors to cash in Toyota Motor Corp. and other recent gainers.
Market sentiment turned bearish as some key members of the ruling Liberal Democratic Party were seen opposing the bills, whose fate will be decided in an upper house vote on Monday.
Prime Minister Junichiro Koizumi has said rejection of the bills, opposed by many in the party, would be tantamount to a vote of no-confidence, a tacit threat to call an election.
The Nikkei ended down 116.83 points at 11,766.48. The broader TOPIX index fell 1.24 percent to 1,189.19.