Kusa

A Japanese internet slang expression meaning laughter. Used to express amusement or that something is funny, much like "lol" in English. It can appear on its own at the end of a sentence, or in verb forms such as "kusa haeru" (grass is growing) and "kusa haeta" (grass grew).

Translated literally, kusa simply means "grass," which makes absolutely no sense without knowing the context.

Before "kusa" came along, the letter "w" was widely used online as shorthand for laughter. When typed repeatedly as "wwwww" to express heavy laughter, the string of w's visually resembled blades of grass sprouting from the ground, which gave rise to the expressions "kusa" (grass) and "kusa haeru" (grass is growing).

The term took hold in the early 2010s, primarily through Niconico Douga and the nanJ board on 2channel.

The Origin of "w"

"W" comes from the first letter of "warai" (笑い), the Japanese word for laughter written in romaji. The prevailing theory traces it back to online game chat environments in the late 1990s.

However, alternative theories attribute its origin to internet forums like 2channel or real-time chat platforms, and the exact origin remains debated.

The Evolution of "Laugh" in Japanese Internet Slang

The way laughter has been expressed online in Japan has shifted over the years. In the early days of 2channel, founded in 1999, the notation "藁" (wara) quickly became the dominant form. The kanji 藁 literally means "straw," but its meaning was irrelevant; it was chosen purely for its sound. "Wara" has the same sound as "warai" (笑い, laughter), and using it instead of the standard "笑" fit 2channel's culture of favoring unconventional expressions. By the early 2000s, "w" began to take over, and around 2003 it replaced 藁 as the mainstream form.

Derivative Expressions for Intensity

"Kusa fukahi" (草不可避, literally "grass unavoidable") means that laughter is unavoidable; something is so funny you cannot help but laugh no matter what.

There are also escalating expressions like "kusa koete mori" (草超えて森, "beyond grass into forest"), which raises the scale from grass to woods to forest, emphasizing that something is too funny for a mere "kusa" to cover.