Osaka voters rejected a referendum proposal Sunday to merge the city into five semi-autonomous wards, dealing a crippling blow to Mayor Toru Hashimoto.

“I will continue on as mayor until my term expires, but I will retire from politics after that,” Hashimoto said at a news conference Sunday night, reiterating his earlier promise to retire from politics when his current term expires in December.

The turnout rate was 66.83 percent, 5.91 points higher than that of Osaka’s double gubernatorial and mayoral elections in 2011. But the margin of victory for the merger opponents was razor thin — just over 10,000 votes — with the final tally 705,585 votes against versus 694,844 for it.