Japanese knives--correct angle?

[mhoffman81]

Does anyone have experience sharpening one-sided Japanese kitchen knives? As you probably know, these have a bevel on one side only; the other side is flat. I have a set of Masahiro knives. They've been badly sharpened in the past (my doing, sigh), so there's no hint of the original bevel. I'd love to know the correct sharpening angle...or any other tips to bring these fine knives back into trim. Thank you!