I am new to karate. I noticed there are cases where you don't say 'osu' (pronounced 'oss'), for example when bowing at the beginning of a kata. But in most cases you do say ' osu' when bowing. There are many times when students respond with 'osu' to the sensei. So is there a set of rules for when to say that word during training, sparring, speaking to your sensei after class etc.?
Ok, before all the uban legends begin to grow here, you first need to know what "osu" means and what its origins are. As to origin, there is no one single source which is right. Some say it's derived from "onegaishimasu", where the initial and trailing syllables are kept and everything else is discarded. Ever hear a drill sergeant scream "TEN-HUT!" and everyone jumps to attention? Well, "ten-hut" is a derivative of "attention", much like "osu" derived from "onegaishimasu". Except that "ten-hut" isn't in dispute, whereas "osu" is. Others have other ideas where it comes from - some from regular speech, other say it has military derivations, and so on. Others say this is a phrase that is something women should not be using.
Depending on whom you ask, it can mean anything from "acknowledged" or "ok, got it", to "Waaaasssssuuuuppppp!", to a cheer of sorts.
These are one of these cases where, when in Rome, do as the Romans. If the class screams out "OSU!" at seemingly every response to what the instructor says, then that's what you do. Some karate schools use it as a form of "ok, got it" (while others use the phrase "hai"), while others use it as a sort of "SIR!! YES SIR!!!" response.
People who never heard the phrase before are at a better advantage, because they will walk into a dojo and not say anything, which is proper for anyone who is not a student anyway. Those who are used to using it as "Waaasssssuuuuupppp" and then go visit a dojo run by some ancient relic from the samurai era who seems to have a deal with Death that he will never die... the visitor is going to bitterly annoy the old crony to no end.
So my advice to people who ask: say nothing, and maintain humility. Then when you get used to the lay of the land at a particular dojo, do what everyone else is doing. If you visit or change to another dojo, don't assume "osu" means the same at the next place, so, shut mouth, and watch to see what the locals do.
Osu is generally an acknowledgement of learning or instruction from another person, particularly a teacher or senior.
Apart from instruction, such as how to better perform a technique, it can be in response to being called onto the floor by a teacher to demonstrate something like bunkai or kata. It can also be a response to being given a compliment.
After months of training in my dojo I feel confident enough to answer my question.
The the answer is simple: ossu is said only when bowing or responding to a person.
When "Ossu" is said in the dojo I train:
- Bowing to the Sensei at beginning/end of class, before/after break,...
- Before you spar (various forms of kumite) you bow to your partner
- Acknowledging a command from the Sensei, advice about improving during class
- Sensei gives trainee a reinforcement for performance or asking a good question
When do you bow without saying "Ossu" in the dojo I train:
- At end of class we bow to the Shome following the tradition
- At the beginning of execution of a Kata, we bow but not to someone in particular. This is considered to be part of the kata.
There is probably no right and wrong ; there is merely a given set of rules and conventions in each d ojo /organization /discipline.