In sports the gold medal is the highest level but in Bujinkan we think that the bronze medal is the highest level.
青銅 The first kanji is AO and means blue or green (when some one says ao it can mean both blue and green!). The second kanji DOU means copper.
銅 DOU can lead electricity and is more useful than gold. In taijutsu we take the natural 道 DOU (way or path). The way is not decided until the opponent has taken his position, like electricity doesn’t jump from one place to another before it can. Taijutsu is the same, we can not do the technique before the opponent has given us the opportunity where it comes natural. This is the 道 we should take.
Then Soke said look how I take this punch with my 胴 DOU (body, trunk, waist) and laughed.
This is the play of words and kanji Soke often does. I think he does this to break patterns and make us think in different ways we usually thinks. Building new synapses in the brain. Shortly after this he spoke about hijoushiki (see my other post about that).