what makes this particular onsen special is that it's actually a river. the hot spring comes bubbling up from the riverbed --they've basically blocked off parts of the river to make a few outdoor baths.

the food was pretty good too. they did a cool presentation with the sashimi. i guess this is supposed to be a kamakura, or a japanese igloo. notice the prawn chilling out next to a scallop and a mound of wasabi:
it snowed on our second day there, so we sat in a bath watching snowflakes melt amidst the steam.