By Ohmori Toshiyori
Translated by Alex Bennett

If you’ve trained in karate or other martial arts, you’ve probably encountered the term “OSU” (also spelled “OSS”)—a word that conveys respect, determination, and shared purpose. But have you ever wondered about its origins? Actually, a lot of people have, and a quick search on the internet will uncover all sorts of origin theories. All of them are basically incorrect…
This new book explores the fascinating evolution of this iconic term, tracing it from its humble beginnings at a Japanese university to its status as a universal symbol in martial arts worldwide. The author of the book, Ohmori Toshiyori, contacted me during the pandemic and asked if I would be interested in translating his research into the beginnings and true meaning of OSU. How could I possibly refuse?!
Without wanting to give too much away here (hint, please buy the book), the story of OSU begins at Takushoku University (Takudai), where members of the university’s sumo club first began using the term as a greeting. Drawing inspiration from the essence of sumo itself, OSU embodied the sumo principle of “enduring and pushing through”, representing the physical and mental resilience central to the sport. Unlike the commonly shortened version of ohayō gozaimasu (good morning), which sounds exactly the same, OSU was a term of grit and dedication, one that echoed the club’s values and never-say-die mindset.
The university’s educational ideals, shaped by a prewar colonial ethos of resilience and advancement, resonated with the sumo club’s creed of “push through, and all will open up” and “break new ground with a single push.” Soon, OSU was a greeting among the student body at Takudai students, embodying their shared mission of self-discipline and perseverance.
In the aftermath of World War II, as Japan navigated its first years of occupation, the cultural significance of OSU deepened. During this time, somebody at the university, came up with the kanji 押忍 (OSU) for the first time, and the phrase was adopted as a powerful reminder of endurance and fortitude.
This postwar context gave OSU a transformative meaning, reinforcing the notion that even in the face of hardship, one should persevere. As the term OSU spread throughout the martial arts world via Takudai’s phenomenal karate fraternity, it carried this weight of discipline, endurance, and shared respect—values that aligned perfectly with the ethics of budo. Today, OSU is a global martial arts symbol and is embraced worldwide.
This new book not only delves into OSU’s history but also offers valuable insights into how the word has adapted across generations. OSU’s journey—from early-modern sumo ideals to a universal martial arts term—illustrates how a simple three letter word can embody resilience, unity, and purpose that crosses all cultural boundaries. It is THE definitive book on the true meaning of OSU. It will be available for purchase from January, 2025.

押忍