Tsuru Sennin
means the Crane Hermet is also named Master Shen in the English version. He is the older brother of Tao Pai Pai, the master of Chaozu and Tenshinhan and has been Kame Sennin's rival for hundreds of years.
Because he loves cranes he hangs out near rivers just like this cache where he has hidden under a bridge. You will not find this cache unless you go right under the bridge which is a lot easier said than done. Once your under there it's very east to find. Tsuru sennin will do his best to push you into the river so be very careful not to slide down the slope into the water below. Use your own agility to work out the best way to get under the bridge.
Good Luck! To any future cacher who seeks this cache please take some rocks or something heavy to hold down the cache. It should be safe where it is but it could blow away in a typhoon.