House of Councillors

In practice, governments often tried to ensure legislative majorities, either by forming coalition governments with safe legislative majorities in the first place or by negotiating with part of the opposition, or avoided to submit bills with no prospects of passage,[9] so the House of Councillors rarely voted against the decisions reached by the lower house for much of postwar history: As the Liberal Democratic Party (LDP), founded in 1955, often held majorities in both houses or was sufficiently close to control both houses together with independents and micro-parties for a long period, inter-chamber disagreement was rare during most of the 1955 System.

After the opposition victory in the 1989 election, the relative importance of the House of Councillors initially increased, as the LDP continued to govern alone and did not hold a two-thirds majority in the House of Representatives. Crucial legislation had to be negotiated with parts of the opposition. The most prominent example was the so-called "PKO Diet" (ja:PKO国会, PKO Kokkai) of 1992 when the LDP negotiated and passed the peace-keeping operations bill with centre-left/right-of-JSP opposition parties (DSP and Kōmeitō) against fierce opposition from JSP and JCP; the PKO law became the base for the Self-Defense Forces' first (ground) deployment abroad as part of the UN mission in Cambodia. After the 1993 House of Representatives election, with the exception of a brief minority government in 1994, coalition governments or the confidence and supply arrangement during the restored LDP single-party government ensured legislative government majorities until the opposition victory in the 1998 House of Councillors election which led to the formation of another coalition government by 1999.

The legislative two-thirds override power of the House of Representatives was never used between 1950s and 2008 when the LDP-Kōmeitō coalition government had lost the House of Councillors majority in the 2007 election, but did control a two-thirds majority in the House of Representatives since 2005. After that, it has been used somewhat more frequently (see ja:衆議院の再議決, Shūgin no saikaketsu, ~"Override decisions by the House of Representatives" for a list). If a government controls a two-thirds majority in the House of Representatives and is willing to use it, the House of Councillors can only delay a bill, but not prevent passage.

Opposition control of the House of Councillors is often summarized by the term nejire Kokkai (ja:ねじれ国会, "twisted" or "skewed" Diet). Setting aside the immediate postwar years, when many governments were in the minority in the upper house, but the strongest force, the centrist Ryokufūkai, was not in all-out opposition to either centre-left or centre-right governments and willing to cooperate, the Diet was "twisted" from 1989 to 1993, 1998–1999, 2007–2009, and most recently 2010–2013.

In recent years, many constitutional revision advocates call for reforming the role of the House of Councillors ("carbon copy" of the House of Representatives or "recalcitrant naysayer") or abolishing it altogether to "prevent political paralysis", after the recently more frequent twisted Diets have seen an increase in inter-chamber friction/"political nightmare"s.[10][11] Examples of high-stakes, internationally noted conflicts in recent twisted Diets:

• In 2008, two nominees for BoJ governor by the Fukuda Cabinet (Toshirō Mutō, Kōji Tanami) were rejected by the DPJ-led opposition in the House of Councillors, and the SDF naval support mission for NATO/OEF in the Indian Ocean had to be interrupted for one month while the extension of the anti-terrorism law was delayed by the extended legislative proceedings necessary to override the House of Councillors rejection.
• In 2011, the Kan Cabinet struggled to pass a renewable energy bill and a bond ceiling increase (unlike the budget itself subject to the normal legislative procedure) against the LDP-led opposition majority in the House of Councillors until it negotiated a deal with the LDP in exchange for child allowance reform and the cabinet's resignation which Kan had already announced, but conditioned on the passage of the bills.[12][13]

• 1947 Japanese House of Councillors election
• 1950 Japanese House of Councillors election
• 1953 Japanese House of Councillors election
• 1956 Japanese House of Councillors election
• 1959 Japanese House of Councillors election
• 1962 Japanese House of Councillors election
• 1965 Japanese House of Councillors election
• 1968 Japanese House of Councillors election
• 1971 Japanese House of Councillors election
• 1974 Japanese House of Councillors election
• 1977 Japanese House of Councillors election
• 1980 Japanese House of Councillors election
• 1983 Japanese House of Councillors election
• 1986 Japanese House of Councillors election
• 1989 Japanese House of Councillors election
• 1992 Japanese House of Councillors election
• 1995 Japanese House of Councillors election
• 1998 Japanese House of Councillors election

• 2001 Japanese House of Councillors election
• 2004 Japanese House of Councillors election
• 2007 Japanese House of Councillors election
• 2010 Japanese House of Councillors election
• 2013 Japanese House of Councillors election
• 2016 Japanese House of Councillors election
• 2019 Japanese House of Councillors election
• 2022 Japanese House of Councillors election