What's in a Name?

“It ain't what they call you, it's what you answer to.”― W.C. Fields

Keidanren, the Japan Business Federation, has submitted a proposal to the Japanese government requesting a revision of the law to allow married couples to opt to use separate surnames after marriage. As women's roles in the workforce expand and gender equality advances, the demand for allowing couples to choose separate surnames is increasing. Many modern couples share responsibilities in housework and childcare, reflecting a partnership approach. Despite this, there is strong opposition within the ruling Liberal Democratic Party, with concerns that separate surnames could weaken family unity. During a debate before the upper house election in July 2019, only late Prime Minister Abe Shinzō was among seven party leaders present did not support the idea of separate surnames. Interestingly, the Minister of Justice notes that Japan is the only developed country that still enforces this system.

The tradition of married couples sharing the same surname is relatively recent. Before the early Meiji era (1868–1912), surnames were not commonly used by the general public. Surnames were introduced to improve the family registration system, aiding in tax collection and military enlistment management. Initially, women retained their family surnames. However, in 1896, an amendment to the Civil Code mandated that married couples must share the same surname. This requirement has only been in place for about 120 years.

The Ritsuryo legal system was a legal system based on Confucianism and Chinese legalism which was implemented around the same time as the Taika Reforms, which were implemented in 645. With the start of the Ritsuryo code, the significance of 氏姓 (Uji-Kabane), a clan naming process which had been in effect since the Yayoi Period (300 BC to 300 AD), diminished as family lineage became more important than clan status. 名字 (Naazana) emerged to distinguish subgroups within clans, such as the different lineages within the 藤原 (Fujiwara) clan. Names were often derived from places of origin. Initially, 名字 were not inherited but were eventually passed down starting in the late Heian period, signifying practical identification of families.

As the Ritsuryo system collapsed, samurai groups (武士団/Bushidan) formed, managing nobleman estates or protecting their own lands. They adopted land names as naazana alongside their clan names, and these names were passed to family members. By the Kamakura period, samurai controlled multiple territories and divided assets among children, who adopted the name of their inherited lands.

During the Kamakura period, although samurai had different naazana, their official clan names (ujikabane) remained significant. For example, brothers 新田義貞 (Nitta Yoshisada) and 脇屋義助 (Wakiya Yoshisuke) both had the clan name 源 (Minamoto). The emperor-sanctioned names included a "の" (no) between the clan name and first name, a tradition dating back to the ujikabane system.

In the Edo period (1603-1808 AD), the use of true family names was limited, with naazana functioning as family names do today. The kanji 苗字 (Myouji) replaced 名字. Citizens were registered in local temples with names including their residence, occupation, and first name, e.g., Goro Nagaya no Sempei (Sempei from the longhouse Goro). Samurai had four names: clan name, family name, official nickname, and first name. To protect against "evil spirits," they avoided using their real first names, a custom from China also seen in countries like Thailand, where nicknames are commonly used. Family names became mandatory for all Japanese citizens on February 13, 1875, during the Meiji period. Initially, women retained their family names after marriage. It wasn't until 1896 that both spouses were required to adopt the same surname, typically the husband's. Since 1947, couples can choose which spouse's family name to use.

From 1875 onwards, citizens chose their own family names, often selecting names of prominent families or places, without familial ties. There are regional variations in name distribution; for instance, common Okinawan names like Chinen (知念) or Shimabukuro (島袋) are rare elsewhere in Japan.

Though familiar, common Japanese names represent just a fraction of the vast number of family names, estimated around 100,000, and up to 300,000 with different spellings. To manage the variety, the permitted characters were limited to 843 kanji (人名用漢字, jinmeiyō kanji). Despite this, 10% of the population shares only ten surnames, and the top 100 names cover a third of the population.

Note: The work "A Long History of Japanese Names" by Mami Suzuki was consulted heavily in writing this article.