2 years ago, when I was in Waikiki, I saw this restaurant with a very short line so I didn't bother to try it.
Last week, I was in Waikiki and see how long the line is, I was curious and wanted to try. Many of my friends also told me that this restaurant is worth a try. I did try and not just once but twice. The udon is very good. I got the beef one (niku) and it is very tasty. The price is very reasonable. The first time I try, I waited in line for 25 minutes. The 2nd time I try, I waited in line for 50 minutes, but it's worth the wait.
I would highly recommended this restaurant if you are into udon.