If you spend any time in a Kyokushin dojo, you’ll hear the word Osu constantly. We say it when we bow, when we acknowledge instruction, when we greet each other, and sometimes when we’re just trying to will ourselves through a hard training session. It’s part of the rhythm of dojo life.
Most students in Kyokushin learn that Osu comes from oshi shinobu, “push and endure”. For many, that’s where the inquiry ends. It’s a good answer, and it captures something essential about Kyokushin training. But the actual history of the word is more complicated than that, and understanding the fuller picture helps explain both what Osu means within our system and why not everyone in the karate world embraces it.
What Osu Means in Kyokushin
In Kyokushin, the standard explanation traces Osu to 押し忍ぶ (oshi shinobu), meaning “to push and endure.” From this we teach 押忍の精神 (Osu no Seishin) – the spirit of perseverance. “Osu no Seishin” reflects the very heart of Kyokushin: pushing through challenge, meeting hardship with resilience, and cultivating humility and patience through effort.
The kanji commonly used for Osu, 押忍, reinforce this interpretation: push (押) and endure (忍). These function as ateji, characters chosen not because they reveal the word’s original etymology, but because they express the meaning we want the word to carry. Regardless of where the word actually came from, these kanji express exactly what Osu represents within Kyokushin.
And in practice, that meaning shows up constantly. Osu isn’t just a word in our dojos… it’s an attitude.
We use it as acknowledgment: “Yes, Sensei. I understand.” We use it to express respect when bowing, greeting, or receiving instruction. We use it to reflect spirit, especially when training becomes demanding and we need to remind ourselves to keep pushing. And when the whole dojo answers with one sharp, powerful “Osu,” it creates unity… a shared sense of purpose that defines our training.
This is why the “push and endure” interpretation fits so naturally. In Kyokushin, Osu represents showing up fully, giving your best effort, staying committed, and choosing to endure even when fatigue sets in. It captures the mindset we aim to develop in ourselves and in our students.
Where Osu Actually Comes From
But here’s the reality: the word itself probably didn’t originate with that philosophical meaning at all.
Scholars generally agree that Osu isn’t rooted in classical karate or Okinawan tradition. Instead, it likely emerged in early 20th-century Japan. Possibly in military or university athletic settings, as rough, informal slang among young men.
One widely-cited theory suggests that Osu began as a colloquial contraction of polite greetings like Ohayō gozaimasu (“good morning”) or formal phrases like Onegaishimasu (“please,” “I humbly request”). Over time, it was shortened and roughened into something more casual and masculine.
Because of those origins (slang from outside Okinawa, possibly with militaristic associations) some traditionalists reject Osu altogether. In certain styles or dojos, it’s regarded as informal, crude, even disrespectful, especially when used outside the dojo or toward seniors who expect more formal language.
In other words: Osu has never had a single, uncontested origin. What it means and whether it’s appropriate depends on context, culture, and the community using it.
Osu in Other Martial Arts
You’ll sometimes hear “Oss” in Brazilian Jiu-Jitsu, MMA gyms, and other modern martial arts. Its spread almost certainly came through karate influence. Outside Kyokushin it’s often used simply as a greeting or sign of respect, but it rarely carries the deeper connection to attitude, spirit, and perseverance that we emphasize.
Closing Thoughts
The historical origin of Osu may never be fully settled – it probably emerged from something far less elevated than the philosophy we attach to it. But in Kyokushin, what matters isn’t where the word came from. It’s what it expresses: acknowledgment, respect, unity, and above all the spirit of perseverance that our training demands.
Whether during hard training or at the start of class, Osu reminds us of what matters. In Kyokushin, it isn’t the origin of the word that counts… it’s the spirit behind it.
Osu.
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Learn more about Bill Stewart and Texas Kyokushin Karate, where we continue the Kyokushin tradition in Texas.Connect with me:
Follow Kyokushin Karate Blog on Facebook, Instagram, and X.
Be sure to visit Kyokushinkai Karate, our Facebook group — one of the largest and most dedicated Kyokushin communities online.
Learn more about Bill Stewart and Texas Kyokushin Karate, where we continue the Kyokushin tradition in Texas.
