Kaifu, in Tokushima, is probably the best place to score the quality rivermouth waves. It's about 45min from Cape Muroto, and is in the heart of the scenic Ana Quasi national coastal park. When it turns on it has heavy tubing rights in both the rivermouth and the neighbouring beach. When it's on, it's guaranteed busy, but especially so on Sundays. It can hold a decent sized swell and has been ridden up to 10-12ft (3-4m).