✶ Two houses · 連立政権
233 and 125.
A Japanese government needs 233 of 465 in the House of Representatives to choose a Prime Minister and survive. To pass laws without a fight it also wants 125 of 248 in the House of Councillors — or two-thirds of the lower house (310) to override it. Today's LDP–Ishin coalition has 351 and 120. Build another.
Status
majority two-thirds (re-pass bills; also needed in both houses to initiate an amendment)
Parties in government · tap to toggle
Seats are caucuses (会派), the groups members sit in, from each house's own table; party colours are our own. Vacant seats are grey and count against no one.
How the two houses map
One caucus here,
two parties there.
中道 in the lower house
The CDP and Komeito merged their lower-house members into the Centrist Reform Alliance (中道改革連合) in January 2026 and fought the February election together. After it dissolved in September, its lower-house members — now the Democratic Reform Party and Komeito — kept sitting together as one caucus, 中道. In the upper house, the CDP and Komeito sit apart. So the builder has a Komeito switch and a DRP / CDP switch, and counts the lower-house 中道 caucus only when both are on.
The twisted Diet
When the government lacks an upper-house majority, the Diet is “twisted” (ねじれ国会). The lower house still decides the budget, treaties and the Prime Minister on its own (Arts. 60, 61, 67), but an ordinary bill the upper house rejects needs two-thirds of the members present in a second lower-house vote (Art. 59(2)). The current status is twisted, with an override.
Two-thirds of whom?
The builder draws two-thirds of the full house — 310 and 166. For re-passing a bill that is a safe line, since the Constitution asks for two-thirds of those present. For an amendment it is exact: Article 96 needs two-thirds of all members of each house. Try the bill simulator →
Inside or outside the cabinet
A party can support a government without taking ministries, as Ishin did from October 2025 until September 2026. In the builder, a party is in if its votes count for the government.
Precedent
Thirty years
of coalitions.
- 1993–94
Hosokawa: eight parties against the LDP
After the July 1993 election, eight parties and groups — the Japan New Party, Socialists, Japan Renewal Party, Kōmeitō, Democratic Socialists, Sakigake, the Socialist Democratic Federation and the upper-house group 民主改革連合 — formed a non-LDP, non-Communist coalition under Morihiro Hosokawa on 9 August 1993. The LDP, in government alone since its founding in 1955, went into opposition for the first time. The cabinet lasted until 28 April 1994 and replaced multi-member districts with today's mix of single-member districts and party lists.
Hosokawa cabinet ↗ · 細川内閣 ↗ - 1994–96
Murayama: the LDP backs a Socialist
On 29 June 1994 the LDP joined its old rival the Japan Socialist Party and New Party Sakigake to elect the Socialist leader Tomiichi Murayama Prime Minister, in a runoff against Toshiki Kaifu. The cabinet had 13 Liberal Democrats, six Socialists and two from Sakigake. When Murayama resigned in January 1996, the three-party coalition continued under the LDP's Ryutaro Hashimoto from 11 January.
Murayama cabinet ↗ - 1999
Obuchi: LDP, Liberals, then Komeito
Short of a majority on its own after the 1998 upper-house election, Keizō Obuchi's LDP brought the Liberal Party into cabinet on 14 January 1999, and New Komeito on 5 October 1999.
Obuchi cabinet ↗ - 1999–2009
LDP–Komeito, first period
The partnership formed under Obuchi governed from 5 October 1999 until 16 September 2009, when it lost power at the 2009 general election.
LDP–Komeito coalition ↗ - 2009–10
Hatoyama: DPJ, SDP and the People's New Party
The Democratic Party of Japan won 308 seats and formed a cabinet with the Social Democrats and the People's New Party on 16 September 2009. SDP leader Mizuho Fukushima was dismissed from the cabinet on 28 May 2010 after the dispute over relocating the Futenma air base; Hatoyama's cabinet ended on 8 June 2010.
Yukio Hatoyama cabinet ↗ - 2012–2025
LDP–Komeito, second period
Back in power with a supermajority from 26 December 2012. In October 2024 the pair fell to 215 seats, short of 233, and governed as a minority. On 10 October 2025 Komeito announced it was leaving the coalition over disagreements with the new LDP president, Sanae Takaichi.
LDP–Komeito coalition ↗ - 2025–
LDP–Ishin
After Komeito left, Takaichi formed her first cabinet on 21 Oct 2025 on an agreement with Ishin. Ishin supported the government from outside the cabinet until the 17 September 2026 reshuffle, when Hiroshi Nakatsuka (中司宏) became a minister.
First Takaichi cabinet ↗ · 第2次高市内閣 (改造) ↗