Don't make the mistake of allowing a sharpener to work on your Japanese knives unless they confirm that the work is done by hand on waterstones - not a belt grinder or any other grinding machine. You need to find a service that will sharpen by hand using Japanese waterstones.
Also, ask questions about how long they've been in business and don't be afraid to ask for recommendations. If it's a simple job on an inexpensive double bevel knife then maybe this is overkill but for high dollar high end single bevel traditional Japanese knives having major repair work you need to make sure that the person you're trusting has the knowledge and experience to back up they're talk.
Most professional knife sharpeners are charging a premium for sharpening these knives. Why? It's simple - because they can. They know that these knives are expensive, and have a certain "aire" attached to them. They know that it takes more time and skill to sharpen them and they know that the user understands this so they take advantage of the situation. You pay the premium price while getting the basic service. I'm not trying to badmouth the professional knife sharpening industry but after hearing of hundreds of horror stories I just have to believe that where's there's smoke - there's fire.
We, at JapaneseKnifeSharpening.com do charge more for sharpening these knives than some but less than others and we like to think that we offer a great deal in return. We use a highly refined "hand" sharpening procedure that utilizes between 6 - 10 different waterstones. The resultant edge is strong, highly polished/refined, and is nothing short of "High Performance". It's the best possible edge that can be attained through any sharpening method. It is the edge that your fine Japanese knives deserve.
We do major repair work as well, often times working on family heirlooms and high end knives made by famous makers.
One of my favorite repair jobs that I'm quite proud of is the refurbishment of this 330mm Shigefusa (KIYA) yanagiba owned by Harrleson Stanley (from Shapton USA). This knife was gifted to Harrelson personally by the owner of Shigefusa after having survived a hurricane. The knife was found under sea water as seen in the before picture. I worked on this knife to bring it back to what I believe to be close to what Shigefusa would do themselves.
As you can likely imagine none of this work was done by machine, it was 100% hand work done on waterstones. There's only probably a few pro sharpeners doing this level of work in this county and maybe even the world for that matter so remember - ask for credentials!
Well I really didn't want this post to be a rant but it kind of is non-the-less I guess. My point in all this is for you to beaware of who your handing over you're expensive and very special Japanese knives too.