Japanese surnames and the complexity of their reading
When reading long lists of Japanese names, for example in the credits of a movie or in the list of the hall, there are two contradictory impressions. The first is that there is a list of common surnames that seem to be everywhere. On the other hand, you will always find one or two Japanese surnames that you have never seen – and whose pronunciation you may not know.
Although it sounds incongruous, both impressions have a bit of truth. To begin with, how many Japanese surnames are there? is a difficult question to answer as it depends on how we decide to count them.
The first problem we run into is with surnames that sound the same, but use kanji different. For example, it is kawa which means river, which can be written as 川 or 河. Thus, you can find surnames like 川 原 and 河 原 (Kawahara), 川村 and 河村 (Kawamura), etc.
川 and 河 are read as Kawa, 島 and 嶋 are read as Shima, and 斉 、 齊 、 斎 and 齋 are read as Sai. Some surnames are read differently even if they are the same character, such as 高田 (Takada / Takata)
Things get more complicated when you include characters that are technically the same, but come in different versions. A very common example is shima (island), which is commonly found as 島, but in surnames it can be found as 嶋. Another notorious character is sawa (swamp), whose common version is 澤, which coexists with the simplified version 沢. So does the Sawada family (澤 田) have the same last name as the Sawada family (沢 田), or are they different?
In this sense, the most particular is the surname Saito, whose first character has at least four different versions: 斉 、 齊 、 斎 and 齋. Incidentally, the first two forms are more common in western Japan, while the last two are found in the east and northeast of the country.
They look the same, but they read different
Even if a name has the same kanji, there is a possibility that it will read differently. This is because in a large number of cases there are different readings, so 高田 can be read as Takada or Takata, 河野 can be read as Kawano or Kono, and 東, for some strange reason can be read as Higashi Y Azuma. The name with the most different readings is 丹 生, among whose readings is Nioi, Mibu or Nyuu.
For the above reasons, it is difficult to find the number of Japanese surnames that currently exist. According to site estimates な ま え さ あ ち(Namae Saachi, namesearch), the total number can range from 50,000 to 300,000, depending on how they are counted.
The 10 most common Japanese surnames
According to the site 名字 由来 (Myoji yurai, origin of surnames), the 10 most common Japanese surnames are:
Watanabe (渡 辺)
Yamamoto (山 本)
Nakamura (中 村)
Together, the ten most common Japanese surnames span a population of 12 million people. This barely represents 10% of the population. Note that the 10 most common surnames consist of two characters, and it is a very clear trend. Even within the top 100 there are only three surnames with a single character: Hayashi (林), Mori (森) and Hara (原), and only two surnames with three characters: Sasaki (佐 々 木) and Hasegawa (長谷川).
Strange Japanese Surnames
Japanese surnames with more than three characters are extremely rare. In fact, only one makes it to the top 5,000, Teshigawara (勅使 河 原), with only 3,400 people bearing that last name. Other rare surnames are Kadenokoji (勘 解 由 小路) and Saemonsaburo (左衛 門 三郎).
Other rare surnames stand out for their meaning, such as 辺 銀 (Pengin, penguin);鬼 (Oni, ogre) ;砂糖 (Sato, sugar);回 り 道 (Mawarimichi, deviation), 東京 (Tokyo, whose family ironically lives in Osaka);鰻 (Unagi, eel);猫 屋 敷 (nekoyashiki , cat house).
The winners in the rarest Japanese surname may be 牛糞 (Ushikuso, cow dung), 馬 尻 (Umajiri, horse ass), e 猪 股 (Inomata / Imata, groin of wild boar).