伯父 vs 叔父: Japanese Terms for Aunts, Uncles, Great-Uncles, Grandnephews and Other Relatives, with Readings

伯父 vs 叔父: "伯" if older than your parent, "叔" if younger

The kanji for oji (uncle) and oba (aunt) depend on whether they're older or younger than your own parent (father or mother). Your parent's older brother and sister are 伯父 and 伯母; your parent's younger brother and sister are 叔父 and 叔母. Both are read "oji" and "oba".

伯 is a character for the eldest of siblings, and survives in the word 伯仲 (hakuchuu, "evenly matched"). 叔 is a character for a younger sibling. The usage comes from the old Chinese practice of naming brothers in age order as 伯, 仲, 叔 and 季.

4 common mistakes

• Which side of the family doesn't matter: there's no rule that "the father's side is 伯 and the mother's side is 叔". Your mother's older brother is 伯父, and your father's younger sister is 叔母.
• Their age relative to you doesn't matter: even if your uncle is 2 years older than you, he's 叔父 if he's your parent's younger brother. You always compare with your parent's age.
• An uncle's or aunt's spouse follows the blood relative: the wife of a 伯父 is written 伯母, and the husband of a 叔母 is 叔父. Follow the character of the uncle or aunt related by blood, not the spouse's own age. The relationship is 3rd-degree kinship by marriage.
• Your spouse's uncles and aunts are compared with your spouse's parent: your wife's father's older brother is 伯父 and your wife's mother's younger sister is 叔母. Decide by older/younger relative to your spouse's parent, not your own.

Older generations: 大伯父 and 大叔父 are your grandparents' siblings

Your grandparents' siblings are called "oo-oji" and "oo-oba" (great-uncle and great-aunt). The kanji follow the same idea as 伯父 and 叔父: older than your grandparent is 大伯父/大伯母, younger is 大叔父/大叔母. They're read "oo-oji" and "oo-oba", and can also be written 従祖父 (juusofu) and 従祖母 (juusobo).

Great-uncles and great-aunts are 4th degree, the same as cousins. They count as relatives under the Civil Code but aren't heirs. A parent's cousin (itoko-chigai) has "oji/oba" in the name but is a different person from a great-uncle or great-aunt, so take care (see Second Cousins, Cousins Once Removed and Third Cousins in Japanese).

Younger generations: a nephew's or niece's child is 大甥/大姪, and beyond grandchildren come 玄孫 and 来孫

For younger generations, it's less confusing to learn your own children's line (direct) separately from your siblings' children's line (collateral). In the direct line, from about 5 generations down the terms are ones you'd almost never use day to day.

Your nephew's or niece's child is your 大甥 or 大姪 (grandnephew or grandniece), and from their side you're their great-uncle or great-aunt. It's easy to remember as the reverse of your relationship with your grandfather's younger brother. Representation in inheritance through nephews and nieces only goes 1 generation, so grandnephews and grandnieces aren't statutory heirs of their great-uncles or great-aunts.

Terms from the other person's side, and distinguishing the father's and mother's sides

Kinship terms become different words when you reverse the direction. Learning what you call someone together with what they call you makes it easier to grasp the relationship when you're introduced.

To distinguish the father's and mother's sides, add a prefix, as in "chichikata no sobo" (paternal grandmother) or "hahakata no oji" (maternal uncle). In a slightly old-fashioned usage, maternal grandparents are called 外祖父 (gaisofu) and 外祖母 (gaisobo). On the grandchild side, the children of the child who carries on the family were sometimes called uchimago (inner grandchildren) and those of a married-out daughter sotomago (outer grandchildren), but with the decline of the traditional household system these terms are rarely used now. Legally, both are direct blood relatives of the 2nd degree and are treated the same in inheritance.

How to write them in letters, on gift wrappers and in documents

• Letter addresses and text: add an honorific to the correct kanji, as in "伯父様" or "叔母上様". Between close relatives, "XX-ojisan" (uncle XX) is fine too.
• Condolence telegrams and name cards on funeral flowers: write the relationship as seen from the deceased, as in "甥 XX" (nephew XX) or "姪一同" (all the nieces). Note that it's not the term from your point of view.
• Relationships on resident records or family registers: write the relationship to the head of household or the person listed first (child, wife, child's wife, wife's father and so on); terms like 伯父 and 叔父 aren't used.
• Notifications to your employer: applications for bereavement leave or condolence payments may have a field for the degree of kinship as well as the relationship. You can check the degree for each relationship in the Degree of Kinship Quick Reference Table.

Kinship terms get confusing as soon as one more relationship is added in between. In the Kinship Degree & Relationship Calculator, tapping in order from yourself, such as "father → father → younger brother" (great-uncle) or "older brother → son → daughter" (grandniece), shows the term and reading, an explanation of 伯 vs 叔, and the degree, with a family tree. You can also search the quick reference table by reading in hiragana, such as "oo-oji" or "yashago".

FAQ

How do you choose between 伯父 and 叔父?

Your parent's older siblings are 伯父 and 伯母, and their younger siblings 叔父 and 叔母. It doesn't matter whether they're on your father's or mother's side, or how old they are compared with you. You always compare with your parent's age.

Is a 伯父's wife written 伯母 or 叔母?

伯母. An uncle's or aunt's spouse follows the character of the uncle or aunt related by blood, not the spouse's own age. A 伯父's wife is 伯母, a 叔父's wife is 叔母, and a 叔母's husband is 叔父. The relationship is 3rd-degree kinship by marriage.

What do you call your grandfather's younger brother?

大叔父 (oo-oji). Your grandparents' older siblings are 大伯父 and 大伯母, and younger siblings 大叔父 and 大叔母; they can also be written 従祖父 and 従祖母. They're collateral blood relatives of the 4th degree.

What do you call your nephew's child?

大甥 (oo-oi), also written 甥孫 (seison). For a girl, 大姪 (oo-mei) or 姪孫 (tesson). They're collateral blood relatives of the 4th degree, and from their side you're their great-uncle or great-aunt.

What comes after yashago?

A yashago's (玄孫) child is a 来孫 (raison), followed by 昆孫 (konson), 仍孫 (jouson) and 雲孫 (unson). In degrees, a 玄孫 is 4th, a 来孫 5th and a 昆孫 6th; from the 仍孫 (7th degree) onward they're outside the scope of relatives under the Civil Code.