大叔体（おじさん構文）とは

Uncle-style writing (ojisan kōbun) refers to the characteristic phrasing and message style used by middle-aged men on social media platforms like LINE.

On LINE, it is also called "ojisan LINE". When used by middle-aged women, it is referred to as "obasan kōbun".

The term "ojisan kōbun" originated from a tweet posted in April 2017 introducing a "pretend to be an old man workshop," which featured LINE messages typical of middle-aged men. In this context, "kōbun" means "writing style" rather than its original grammatical meaning. This new usage was selected as the second-place entry in the "Sanseido Dictionary Editors' Choice: New Word of 2022," represented by "ojisan kōbun."

Example sentences:
○○-chan, Ohhā❗
😚Today's lunch was so delicious that I want to eat you too, ○○-chan~😍💕(lol)✋Just kidding😃💗

Good work~٩(ˊᗜˋ*)و
🎵What kind of day was it today😘❗❓
I'm really worried about you(._.)😱💦😰When that happens, you need to eat something tasty🍗🤤 and cheer up😆

There is a lack of perspective from the reader, especially from the female recipient. The sender fails to imagine how their already low self-esteem might be further lowered by their communication method and message content.
They desperately want to attract the recipient's attention and become closer.
They have hidden ulterior motives toward young women.
There is a sensitivity to wanting to close the distance but not be disliked.
There is a difference in perception of written expression between middle-aged and older people accustomed to business emails that include seasonal greetings and updates, and younger generations for whom SNS messaging is a daily norm.
It is speculated that remnants of the feature phone email era have created this unique style.

In September 2021, Meiuzawa Aiyuka, a former part-time AKB member and ramen shop owner, reported sexual harassment she suffered from ramen critic Hanstu Endo. Hanstu posted his opinion on his blog, and his writing style and content became a topic of discussion as being "ojisan kōbun." Regarding this incident, Hanstu did not apologize to Meiuzawa but did acknowledge that his writing was ojisan kōbun, saying, "Good evening. This is an old man's writing (lol) Hanstu Endo www."

At the Game Market in November 2021, multiple comedic card games based on ojisan kōbun were released, such as "Ojisan Message" and "Shall we make some old man writing, Ka Na?😁👍". Despite being doujin card games, the former was still being sold in board game sections of electronics retailers as of 2023.

In 2025, Yoshimoto Ojisan's song "No reply yet Ka Na💦❓ Old man writing😁❗️" was widely used in short videos and TikTok, ranking third in the "Simeji Presents Z Generation Trend Awards 2025" for buzzed artists and songs of 2025. Quoted from Wikipedia.