[3][4] However, no single party has ever won a two-thirds majority in the House of Representatives under the current constitution, although the LDP came close several times, as did the DPJ in 2009.

[5] Laws and rules containing more detailed provisions on parliamentary procedures and the relations between the two houses include the National Diet Law (国会法, Kokkai-hō),[6] the conference committee regulations (両院協議会規程, ryōin-kyōgikai kitei),[7] and the rules of each house (衆議院/参議院規則, Shūgiin/Sangiin kisoku).

[8] 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 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).

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).

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: Article 102 of the Japanese Constitution provided that half of the councillors elected in the first House of Councillors election in 1947 would be up for re-election three years later in order to introduce staggered six-year terms.

[14] It was originally intended to give nationally prominent figures a route to the House without going through local electioneering processes.

[citation needed] Some national political figures, such as feminists Shidzue Katō and Fusae Ichikawa and former Imperial Army general Kazushige Ugaki, were elected through the block, along with a number of celebrities such as comedian Yukio Aoshima (later Governor of Tokyo), journalist Hideo Den and actress Yūko Mochizuki.

[citation needed] Shintaro Ishihara won a record 3 million votes in the national block in the 1968 election.