The tripoint is in the centre of the river. I stood on the west bank at the point where, according to my GPSr and geofererenced 1:25000 topographical maps from http://watchizu.gsi.go.jp/ indicated the Saitama-Tochigi border crossed the shore (direct link is http://watchizu.gsi.go.jp/watchizu.aspx?id=54392500&slidex=2000&slidey=400 - clicking on the tripoint where marked on the map provides WGS84 coordinates of N 36° 11' 58", E 139° 41' 16"). There was, however, no indication whatsoever of any prefectural boundaries "on the ground" here. Ibaraki is the other side of the river, Tochigi to the north and Saitama to the south.
The tripoint is undoubtedly in one of these photographs - click on the thumbnail for the full photo:
The tripoint is just north of the intersection as indicated in the map at http://watchizu.gsi.go.jp/watchizu.aspx?id=54392500&slidex=2000&slidey=0 (depending on the size of your screen you might have to scroll the map left a little bit). Clicking on the tripoint where marked on the map provides WGS84 coordinates of N 36° 12' 25", E 139° 39' 51"). There was, however, no indication whatsoever of any prefectural boundaries "on the ground" here either. The power lines played havoc with my GPSr so it was not possible to get an accurate fix "on the ground".
The following photographs are of the tripoint area and are taken from the road intersection just to the south of the tripoint.. I am standing in Saitama.
|Looking North (the tripoint is probably out of this picture to the right). This photograph is looking mostly towards Gunma|
|Looking North-East (the tripoint is in the centre of this road in all likelihood). Beyond the tripoint is Tochigi, and Gunma is to the left|