1. Basic Principles of Modern Japanese Name Structure
Modern Japanese names consist of a surname and a given name. In contemporary Japan, the surname functions as an identifier for the family unit, while the given name functions as an identifier for the individual.
The standard order of name presentation in Japanese writing is “surname + given name.” This characteristic is shared with other East Asian countries including China, Korea, and Vietnam.
2. Historical Development of Surnames in Japan
(1) Evolution of Surnames from Ancient Times to the Edo Period
In ancient Japan, surnames were possessed only by the limited ruling class. Through the system of uji (氏, uji – clan names) and kabane (姓, kabane – hereditary titles), one’s position and duties within the Yamato court were expressed.
From the Heian period onward, in aristocratic society, myōji (苗字, myōji – family names) developed in addition to uji, and appellations based on residence or territorial holdings came into use.
Among the warrior class as well, from the Kamigakura period onward, myōji based on territorial holdings or the location of one’s residence became generalized. Farmers and townspeople also used myōji, but in the Edo period, the majority could not officially use surnames and were identified by common names or house names (yagō, 屋号). Some wealthy farmers and merchants were able to use surnames publicly with their lord’s permission.
The ancient uji were the true surnames, while myōji were merely common appellations.
(2) The Meiji Restoration and the Obligation to Use Surnames
After the Meiji Restoration, the Commoner Surname Permission Decree was promulgated in 1870 (Meiji 3), allowing commoners to use surnames. However, few actually registered surnames. Therefore, in 1875 (Meiji 8), the Surname Obligation Decree was promulgated, making surname use mandatory for all citizens.
Many commoners chose to use ancestral surnames, but some families opted to select new surnames either because they had forgotten their ancestral surnames or to mark a fresh start. There were also cases where local influential figures or temple monks were involved in surname selection. The surnames registered during this period have been passed down to the present day.
(3) Types and Origins of Surnames
Japanese surnames can be classified into multiple categories based on their origins. Surnames derived from place names are most common, with representative examples including Tanaka (田中), Yamamoto (山本), Kobayashi (小林), and Nakamura (中村).
Surnames derived from occupations include Hattori (服部, hattori – weaver) and Ukai (鵜飼, ukai – cormorant fishing master).
Many surnames are derived from clan names and ancient kabane, with numerous surnames originating from the four major clans: Minamoto (源), Taira (平), Fujiwara (藤原), and Tachibana (橘). Surnames from the Fujiwara lineage are particularly numerous. Satō (佐藤), Itō (伊藤), Katō (加藤), Saitō (斎藤), Gotō (後藤), Andō (安藤), and Kondō (近藤) all combine place names or official positions with “tō” (藤), an abbreviation of “Fujiwara.”
3. Japanese Given Name Naming Customs
(1) Basic Functions and Evolution of Given Names (Imina)
The given name (imina, 諱, imina – true name) is the most fundamental element for identifying an individual. From ancient times through the medieval period, imina were considered sacred and were not used in daily life. Instead, common names (tsūshō, 通称) or courtesy names (azana, 字) were employed.
In the Edo period, among the warrior class, the custom of changing from childhood names to formal imina at coming-of-age ceremonies (genpuku) was established. It was also common to change one’s name at life milestones or when receiving henkī (偏諱, henki – one character from a lord’s name).
(2) Naming Based on Seasons and Nature
In Japanese naming customs, seasons and natural phenomena are important sources of inspiration. Children born in spring tend to receive characters such as haru (春, “spring”), sakura (桜, “cherry blossom”), hana (花, “flower”), or me (芽, “bud”); summer births receive natsu (夏, “summer”) or ryō (涼, “cool”); autumn births receive aki (秋, “autumn”), kaede (楓, “maple”), mi (実, “fruit”), or ho (穂, “grain”); and winter births receive fuyu (冬, “winter”) or yuki (雪, “snow”).
Naming based on lunar calendar months has also been widely practiced. Names derived from traditional month names such as Mutsuki (睦月), Yayoi (弥生), Satsuki (皐月), and Hazuki (葉月) exist.
(3) Naming Patterns Based on Birth Order and Gender
In traditional naming customs, birth order is an important element. For males, there was a widespread custom of including ordinal numbers in names: Tarō (太郎, tarō – first son), Jirō (次郎, jirō – second son), and Saburō (三郎, saburō – third son). These could be combined with characters other than rō (郎), such as matsu (松, “pine”) or o (雄, “male”).
(4) Reflection of Parental Wishes and Virtues
Parents commonly imbue their children’s names with their wishes and expectations. Characters expressing wishes for health such as ken (健, “healthy”), kō (康, “peace”), and kotobuki (寿, “longevity”); for wisdom such as chi/tomo (智, “wisdom”), sō (聡, “intelligent”), and ken/kashiko (賢, “wise”); for strength such as tsuyoshi (強, “strong”), gō (剛, “sturdy”), and bu/take (武, “military”); and for gentleness such as yū/masa (優, “gentle”), wa/kazu (和, “harmony”), and jū/yasu (柔, “soft”) are frequently used.
Among the warrior class, characters representing bushidō virtues such as chū (忠, “loyalty”), gi (義, “righteousness”), shin/makoto (信, “trust”), yū/isamu (勇, “courage”), and bu/take (武, “martial”) were preferred.
(5) The Tradition of Tsūji and Henkī
In many family lines, there exists the custom of tsūji (通字, tsūji – generational character), where specific characters are passed down across generations. This serves as an important marker of family continuity. For example, a pattern where all males in a family line have the character masa (正) in their names.
In warrior society, the custom of henkī (偏諱, henki – receiving one character from a lord’s name) was emphasized. This functioned to demonstrate lord-vassal relationships.
4. Issues of Character Selection and Notation
(1) On’yomi, Kun’yomi, and Nanori-kun
Japanese kanji have both on’yomi (音読み, on’yomi – Sino-Japanese readings) and kun’yomi (訓読み, kun’yomi – native Japanese readings). In names, there also exist special readings called nanori-kun (名乗り訓, nanori-kun – name readings). For example, the character chi (智) is normally read as “chi,” but in names it may be read as “tomo” or “sato.” This diversity becomes a factor making it difficult to infer readings in genealogical research.
The existence of multiple kanji with the same pronunciation also increases notational complexity. For example, the name “kaori” can be written with various notations including Kaori (香), Kaori (薫), Kaori (馨), and Kaori (佳織).
(2) Use of Variant Characters and Colloquial Characters
In addition to standard characters, kanji have variant characters (itaiji, 異体字) and colloquial characters (zokuji, 俗字). Since notation in family registers maintains the character forms used at the time of registration, the same individual may be recorded with different character forms in different documents. For example, Sawa/Taku (澤) and Sawa/Taku (沢), Sai/Itsu (齋) and Sai/Itsu (斎), and Hen/Be (邊) and Hen/Be (辺) are different forms of the same characters.
During the compilation of family registers in the Meiji period, there are many cases where notation was not standardized due to scribes’ judgment or regional customs. This becomes a factor complicating searches in genealogical research.
(3) Ateji (Phonetic Borrowing)
Japanese naming customs include the tradition of ateji (当て字, ateji – characters used phonetically), where characters are borrowed solely for their sound without regard to their original meaning or reading. Beginning with the notation of foreign words such as Amerika (亜米利加, “America”), phonetically-oriented notation has also been employed in personal names.
5. Changes to Names
(1) Reasons for Name Changes
In premodern Japan, names were sometimes changed in accordance with life milestones or changes in social status. Particularly among the warrior class, name changes at coming-of-age ceremonies, succession to family headship, and receiving henkī from one’s lord were common. Records of these name changes provide important information for tracing an individual’s life trajectory. In genealogical research, one must always be aware of the possibility that a single individual had multiple names.
In modern times, name changes are possible with family court permission but are rarely conducted. Recognized reasons for name changes include inconvenience in social life, traditional name succession, and religious reasons.
(2) Women’s Names and Tracking Marriages
Japan has adopted a system of married couples sharing a surname, so upon marriage one party changes to the other’s surname. It is common for women to take their husband’s surname. Family registers record the maiden name (kyūsei, 旧姓) and the names of the biological parents.
