Tozan Bayashi is a Japanese style of music that is unique to the Tsugaru region.
Tozan bayashi consists of three instruments: 太鼓 (taiko) drums, 笛 (fue ) flute, and 鉦 (kane) hand cymbals.
There are two different flutes that are used during oyama sankei. The first is for tozan bayashi, which is for climbing the mountain, and the second is for gezan bayashi, which is for the descent. The flute used for the ascent is long, thick, and has a lower sound, where as the flute used for gezan bayashi is shorter and has a higher cheerful sound. When it comes time to climb down the mountain the music changes to the higher pitched flute to symbolize the relief that the people’s prayers have been heard after oyama sankei.
The other instruments don’t appear to have a set meaning like the flutes, but I think the purpose is so the sound of the kane and taiko rings through the mountain and wakes up the kami sama (a god in Shintoism) that is Iwaki. During gezan bayashi the rhythms of the cymbals and drums change as well to a faster more upbeat rhythm.
I think tozan and gezan bayashi are very unique in that they are location specific. It is such a beautiful cultural aspect that is so specific to the area surrounding Mt. Iwaki.
Here are a couple of links were you can find more info and listen to how it sounds～