House of Representatives lawmakers with family members who were also politicians totaled 120, or 25. 8 percent of all candidates who were elected in the latest lower house election, the Mainichi Shimbun has found.

The figure is down three people from the 2014 general election, in which 123 "hereditary" candidates were voted into the lower house.

In aggregating the information, "hereditary politicians" are defined as either those whose fathers or mothers (including in-laws), or grandfathers or grandmothers (including in-laws and adoptive), were Diet members; or those running in the same electoral district as a former Diet member within three degrees of kinship.

Currently, the number of hereditary politicians in the lower house is highest among Liberal Democratic Party (LDP) lawmakers at 96 members, followed by the Party of Hope at 11 members, the Constitutional Democratic Party of Japan (CDP) at six members, and Komeito at one. Six people who ran successfully as independents are also hereditary politicians.

Among LDP candidates, 103 were "hereditary," only seven of whom lost in the election. Most hereditary candidates inherited strong bases of electoral power, guaranteeing an advantage over other candidates, including LDP Vice President Masahiko Komura's son, Masahiro (Yamaguchi No. 1 constituency), and former Prime Minister Yasuhiro Nakasone's grandson, Yasutaka (proportional representation in the north Kanto bloc).

The proportion of successful hereditary candidates among all successful candidates by political party was 33.8 percent in the LDP, 22.0 percent in the Party of Hope, 10.9 percent in the CDP and 3.4 percent in Komeito.