, meaning reformist political parties or progressive political parties, is an umbrella term used in Japan to refer to a variety of left-leaning political parties generally viewed as "anti-conservative." In the postwar period, it has generally been applied to democratic socialist, social democratic and socially progressive parties that seek to uphold Article 9 of the Japanese Constitution. Japan's "progressive parties" are basically opposed to constitutional amendments led by right-wing conservatives, so they are partly in solidarity with moderate liberal parties. "" parties have been considered progressive or radical-liberal forces.
In general, while the Liberal Democratic Party (LDP) has a strong conservative tendency, the Japanese Communist Party (JCP) has shown a strong progressive tendency in the Japanese political spectrum. In the 21st century, not only traditional democratic socialist parties but also some liberal parties began to be regarded as part of the in the Japanese political context.
The terms "" and have been criticized for being misused by mainstream Japanese media and Japanese conservatives as red-baiting terms to attack South Korean liberals for their historically-motivated anti-Japan sentiment. By South Korean political standards, the Democratic Party of Korea (DPK) does not classify itself as a "" () because it is generally considered socially conservative. However, major Japanese media often refer to the Democratic Party of Korea as a "."
South Korean liberals criticize mainstream Japanese media and conservatives. According to Moon Chung-in, Japanese conservatives pointed out that referring to South Korean liberals as "" is red-baiting, equating them with the Japan Socialist Party and the Japanese Communist Party. Moon Chung-in also said that Moon Jae-in government and DPK support "" () in the South Korean political context, but not "" () or revolution in the Japanese political context.