The ruling parties on Thursday night ignored an opposition boycott of a Lower House plenary session and passed a controversial bill that would cut 20 seats from the chamber. Passage came around 8:30 -- 7 1/2 hours after the session was to open. It was the second time in as many nights that the ruling coalition used its majority power to push the bill closer to law -- and despite an opposition boycott. On Wednesday night, a Lower House committee approved the seat-cut bill. The opposition camp -- the Democratic Party of Japan, Social Democratic Party and Japanese Communist Party -- called the committee's approval of the bill invalid and demanded that Lower House Speaker Soichiro Ito not convene Thursday's plenary session. It also said it did not accept the schedule decided by the chairman of the Lower House Steering Committee during the boycotted meeting. The Diet affairs chiefs of the three ruling parties -- the Liberal Democratic Party, Liberal Party and New Komeito -- had agreed they would try to have the bill clear the Lower House on Thursday and strive for early approval in the upper chamber. The bill, which would trim 20 seats from the 500-member Lower House, was submitted by the ruling bloc. It is being championed by Liberal Party chief Ichiro Ozawa in his crusade to move Japan toward a two-party democracy by doing away with the proportional representation seats on which numerous small parties rely. And the strong-arm tactics being used by the ruling camp appear to indicate that it regards the bill's passage as necessary to maintain coalition unity. The LDP had promised the Liberal Party in December that it would get the bill passed, and the Liberal Party had threatened to leave the coalition unless the LDP made good on that promise at the "beginning" of the current Diet session. In addition, the ruling parties had been desperate to get the bill through the lower chamber by today so it could begin full-fledged deliberations on the fiscal 2000 budget, which the government has said is necessary to an economic recovery. There were fears, however, that Diet's paralysis could have forced Prime Minister Keizo Obuchi to dissolve the legislature in order to break the deadlock and avoid the risk of appearing dictatorial. "The problem is the attitude of the ruling bloc, which is trying to do anything to maintain the coalition," said Hajime Ishii, vice president of the DPJ, early Thursday. DPJ President Yukio Hatoyama also strongly criticized the ruling parties and the way they are handling the bill. "Now is the time to fight," he told DPJ Diet members at a meeting. Torn between conflicting demands from the ruling and opposition camps, Lower House Speaker Ito offered a mediation plan earlier in the day to postpone the vote in the Lower House plenary session until next week. Ito's suggestion, however, was later withdrawn as the ruling camp, which insisted that the vote be held Thursday, attacked his offer. "I told (the speaker) that we have reached the limit of our patience," said Hirohisa Fujii, secretary general of the Liberal Party.