It is said that many of Japan's best Marxist thinkers are economists. More surprisingly, "nearly half of the faculty of Japan's economics and business departments were Marxist economists after the war," according to Furihata Setsuo (Jing Zhao, "Review of Furihata Setsuo, Nihon Keizai no Kozo to Bunseki," H-Japan, H-Net Reviews, December 1998). It is no wonder, then, that, for all their subservience to Washington, Japan's power elite have been among the least neoliberal of all power elites of the North, and, economically, they have been well to the left of most social democratic parties in Europe outside Scandinavia in the recent decades after the end of post-WW 2 boom. They rejected Marxism ideologically but their economic thought absorbed the influence of Marxism.
Moreover, they are conservative in the true sense of the word, unlike the so-called conservatives in the USA and the UK. Even as parliamentary communists, as well as social democrats, worldwide, with the exception of Cuba and Venezuela, rejected Marxism and many of them even abandoned Keynesianism to boot, Japan's right-wing power elite cherished the conservation of the status quo, so such neoliberal policies as they have adopted have been far less radical than the kind that most leftists, when in power, put into practice, in the South as well as the North.*
That is why Japan's Right have presided over the world's longest-standing de facto one-party state, and all significant policy struggles take place within the ruling Liberal Democratic Party, not between parties.** The Left in Japan are essentially irrelevant. While the Left's social policy (toward women, zainichi, immigrants, etc.) is marginally better than the Right's, their economic policy today is hardly distinguishable from the LDP's policy a couple of decades ago, and such distinctions as can be found are merely negative: opposition to privatization, labor law reform, higher consumption taxes, etc. When the difference is not merely negative, it puts the Left to the right of the LDP in zeal for protectionism: e.g., "Since 1995, the Japanese Communist Party (the JCP) politicians dominated the testimony advocating for Japan's adoption of safeguards.45 In 1996, the JCP's party effort was at its peak testifying at eleven occasions requesting the government's adoption of safeguards. The JCP's strong interests in GATT/WTO-legal instruments are surprising given its long-standing position against GATT/WTO" (Megumi Naoi, "Shopping for Protection: The Politics of Choosing Trade Instruments in a Partially-Legalized World," Conference on Japan and the World, Yale University, New Haven, Connecticut, 9-10 March 2007).
Combine that with the Left's astonishing position: "Defend all the provisions of the Constitution, including the preamble, and in particular strive to have provisions of peace and democracy fully implemented" (Program of the Japanese Communist Party, the JCP 23rd Congress, 17 January 2004). What kind of Left defends Japan's constitution in its entirety (including Article 29, which says that "The right to own or to hold property is inviolable"), arguing that the constitution that the people of Japan had no part in writing, imposed as it was by the occupation authorities from above, is an expression of "the principle that sovereign power resides in the people" (Program of the Japanese Communist Party, the JCP 23rd Congress, 17 January 2004)? Such a Left can never win, nor do they deserve to win.
* If Japan is like Turkey in ideology and foreign policy, it is like Iran in economic statism.
** Japan is like Iran in this respect as well, except Iran, having a far more rebellious and politicized working class than Japan as well as the history of Jacobinism, is as democratic as any nation can be under class society whereas Japan isn't democratic in the least.