Well, the unbendable arm can be explained using knowledge of physiology: if you relax the antagonist muscle (i.e. the bicep) it takes less effort to keep the arm straight. If you're looking for proof of some mystical energy, that's probably not the place to start.
KI is attitude, in martial arts it means fighting spirit. Any mystical connotations are just that..mystical.
Unfortunately being the language of another country, and not even a Romance language, there are no direct, word for word, translations of many Japanese terms. It's important not to get wrapped around the axle about these things to the point where training is negatively effected. In my training, we rarely use the term "ki" when speaking about technical aspects of aikido. Rarely will you ever hear someone advise a student to "extend/project ki" to make a technique work as that is often a nebulous concept for many.
Hey baby, you really fill out that gi in all the right places, oh yeah... Nah, it's langauges that descend from Latin. Mitch
The arm isn't actually unbendable, if someone hits it with a sledgehammer it bends just fine. Go try it. The Bear.
More than likely the OP is a beginner and there are still too many aiki bunnies out there spouting mystical crap to hide bad technique. Not his fault.So long as he doesn't BUY££££ into it.
Can Ki be proven? It really depends on your take on Ki. If you're talking about the mystical energy of the universe or the life force of the universe ideas sometimes expressed by people who talk about Ki then, no. It can't be proven. If on the other hand you consider Ki to be a generic term for energy which can be used to describe many different things then, yes. It can be proven. I would mostly agree with Koyo that Ki in martial arts is attitude. It's your state of mind. The unbendable arm, which isn't truly unbendable, apart from being a useful basic skill to have in Aikido is simply an exercise to promote self-confidence. When you have a positive state of mind and your confidence is high, you "feel good" because of the physiological effects that has on the body. It's like turning on the taps to the bodies energy reserves. Generally speaking the more energy you make available to you body the better it should perform. You should feel stronger, faster and sharper. And clearly when you're feeling negative and your confidence is low the opposite is true. It's also my experience Ki is a term used to describe things like the direction of movement and focus. Which are things that do not need to be proven. When Bob is moving towards you it's self-evident. Similarly when you are the focus Bobs' attention that's also fairly self-evident. At least it is if you're paying attention. Be wary of teachers who over use the word Ki. They are obfuscating the truth behind a vale of mysticism. Incidentally it's my understanding that the kanji for the word Ki represents a pot of steaming rice covered over with a lid. So Ki is either energy or dinner. Which amounts to the same thing really.
Ki is actually used a lot in technique names....kimusubi or ki osae do giri, etc. Ki Osae Do Giri for example suggests that one controls the opponent's ki with yours; in reality, your getting 'all up i his grill' and putting him on the defense tactically, emotionally, and technically...but the same concept applies. Oh, these are weapons techniques...we have 97 in our system (we had something like 200, but most we chopped them down to 97 and put them into a separate class called Aiki Buki in order to shorten tests up to around an hour and make the requirement list a little more palatable...while still offering more weapons training for those who want it).
....haha, sorry. My point being that there is a practical use of ki...but all too often its a crutch people use when they can't properly articulate how a technique works. This is almost always asked by my teacher during shido ho portion of yudansha shinsa....teacher asks: "But how does this work?" Student replies: "Well sir, you extend you ki and they go down." Teacher smiles on the inside and asks: "But I don't understand what this 'ki' you speak of is...what do you mean?" Which then goes on for several minutes (depending on the testing candidate) while teacher asks questions that guide the student to correct answer. Just had a thought: extending ki is something that happens during a properly executed technique vice something that an individual actually specifically does....does that make sense? Unless you are launching ki balls of energy of course (which people claim to be able to do).
Lol....one person actually deluded himself, and his students, into thinking his ki balls were so real he actually had a local news program come to his school and put it on their evening news (or probably morning news). He failed. He also failed to knock the reporter lady down with his dim mak...which made her kind of mad. She held it in, but you could tell she was holding it in. Her response to his dim mak was "it just seems like you hit my neck kind of hard" while when the teacher did it to his students they went flying all over the place. Oh yeah, he said his ki balls could stop someone's heart so he only wanted to do it on his students instead of the media lady!
There is no mystery to ki. It is simply awase (blending) With the attacker's attitude/intention. Show a stronger fighting spirit master timing and distancing and you shall prevail. Photo one. Blend/avoid his strength and unbalance him (leading his ki) Photo 2 Cut through his attack using triangular entry and timing (suppress his ki) Photo 3 Strike through his INTENTION to attack (deny him ki) Leave out the word ki and it becomes avoid and spend his attack. Cut into his attack and deny him the chance to attack, NO MYSTERY.
In order for ki to work and be present, it has to exist in many places most practitioners are not focused on (like the little toe), and as soon as you begin to focus on it, you loose mushin, and a bunch of other things that I could say in japanese, but would require my ki to actually look them up Ki happens.
