It's just sad that someone is as narrow minded as that teaches, as they say, no such thing as a bad student... I wonder what attitude his students have? Maybe suggesting that he visit your class to show him what aikido is really like, he may have seen a bit of aikido in the past that's left him a bit confused. It has been written in several books, that aikido isn't an effective art, an opinion I feel to be written in ignorance.
Aikido is the best...
