Definition: Kusaeru (草生える) is a Japanese internet slang term that literally translates to ‘grass grows.’ It is used to express laughter in digital spaces, evolving from the shorthand ‘w’ (which looks like blades of grass) to the verb form used today.
If you have spent any time on platforms like X (Twitter) or 2channel in Japan, you have undoubtedly seen the letter ‘w’ appended to the end of sentences. To the uninitiated, it looks like a typo, but in the Japanese digital landscape, it is the fundamental unit of laughter—the equivalent of ‘lol’ or ‘lmao.’ When that laughter becomes intense, the Japanese say that the grass has started to grow: kusa ga haeru (grass grows), which shortened over time to the verb kusaeru.
Living in Tokyo, I remember the first time a younger colleague showed me a thread full of ‘wwwwww.’ It looked like a field of wheat. He explained, ‘It’s just so funny that the grass is growing everywhere.’ It is a fascinating example of how Japanese internet culture creates visual metaphors for abstract emotions.
The Evolution: From ‘w’ to ‘Kusaeru’
The history of this term is rooted in the early days of Japanese bulletin boards. The word for ‘laugh’ is warau (笑う). Gamers and netizens shortened this to just the first letter, ‘w’. Because ‘w’ resembles grass blades, someone eventually remarked, ‘Grass is growing here’ (草生える) when a thread became particularly hilarious. Now, kusaeru is the standard way to describe the act of laughing at something online.
Common Mistakes Foreigners Make
The biggest mistake is using ‘kusa’ or kusaeru in formal business settings. Just as you wouldn’t sign an email to your boss with ‘lol,’ never use kusaeru in a Shinchoku-hokoku or any professional correspondence. It is strictly for casual, digital, and often anonymous interaction.
Another pitfall is using it in spoken, face-to-face conversation. While younger generations might ironically say ‘Kusa!’ out loud, it can sound incredibly jarring or ‘cringe’ if you are not deeply integrated into that specific social group. It is, by design, an internet-native phenomenon.
Pro-Tip: If you are unsure whether your Japanese counterparts are using this term, keep an eye on their use of Donbiki—if someone is posting things that are meant to be ‘cringe’ or ‘weirdly funny,’ you will see kusa appear in the replies. If you use it prematurely, you might find yourself on the receiving end of a confused stare!
Slang Variations
The language is constantly evolving. You might see taikusa (大草原), which means ‘great grassland’—this is used when something is exceptionally, hysterically funny. Think of it as the difference between ‘lol’ and ‘LMAO I’m dying.’ If the ‘grass’ is everywhere, the user is implying the content is pure gold.
User A: Did you see the latest fail video?
User B: Yeah, I literally grassed (草生えた).
Ultimately, kusaeru captures a very specific, slightly detached form of amusement that defines modern Japanese web culture. By understanding it, you gain a better grasp of how Japanese people express themselves when they are behind a screen, away from the rigid expectations of the ‘real world.’
