On August 8, the Democratic Party of Japan held a joint plenary meeting of the party members of both Houses in the Diet building. The meeting approved September 10 as the date of official announcement for the 2012 DPJ Presidential Election, and September 21 as the voting date.

At the meeting, Secretary General Azuma Koshiishi proposed, “For the forthcoming presidential election, we would like to schedule the announcement on September 10, have 12 days for campaigning, including the voting day, and conduct an extraordinary party convention to elect the new party president on Friday, September 21.” Koshiishi also stated that in accordance with precedent, only DPJ Diet members were qualified to run for party president. In doing so, he excluded those who were candidates for the next general election. He called an approval of this, and it was accepted with applause.