Translation guide
In Japanese, the term for 'first child' depends on context: whether you're talking about your own child, someone else's child, or using a general term. The most common and neutral word is 長子 (choushi), but in family contexts, 長男 (oldest son) or 長女 (oldest daughter) are more specific and natural.
A neutral, general term for the first child in a family, regardless of gender.
A formal, written term for the first-born child. It is gender-neutral and used in official contexts or when gender is unknown.
長子としての責任を感じる。
I feel the responsibility of being the first child.
Literally 'first child', used in formal or statistical contexts, like birth order. Common in news or medical settings.
第一子が生まれました。
Our first child was born.
Specifically referring to the first-born son in a family.
The most common word for 'oldest son'. Used in both formal and casual contexts when referring to one's own or another's first-born son.
彼は長男です。
He is the oldest son.
うちの長男は大学生です。
My oldest son is a college student.
Specifically referring to the first-born daughter in a family.
The most common word for 'oldest daughter'. Used in both formal and casual contexts.
彼女は長女です。
She is the oldest daughter.
長女は来年結婚します。
My oldest daughter is getting married next year.
When speaking humbly about one's own first child to others.
Literally 'the child above', this is a common, casual way to refer to one's older child, often the first-born, in contrast to younger siblings. Used in daily conversation.
上の子が小学校に入りました。
My older child started elementary school.
Emphasizes 'the very first/oldest child'. Used when there are multiple children.
一番上の子はもう中学生です。
My oldest child is already in junior high.
When speaking respectfully about someone else's first child.
Adding the honorific prefix ご (go) to 長男 or 長女 makes it polite when referring to another person's oldest son or daughter.
ご長男はおいくつですか。
How old is your oldest son?
ご長女のご結婚おめでとうございます。
Congratulations on your oldest daughter's marriage.
長男 and 長女 are standard terms for 'oldest son/daughter' and can be used for both one's own family and others'. 上の子 is a casual, humble expression used only for one's own child, often in contrast with younger siblings. It does not specify gender.
In Japanese, it's common to refer to family members by name plus a kinship term, especially when speaking to outsiders. For example, instead of saying 'my first child', you might say '太郎 (Taro), my oldest son'.