Do not come to this restaurant if you are an experienced eater of quality Japanese food. I had dinner here recently with a party of 7 and we found the food to be terrible. I was treated, if that's the right word, to a free meal at Koi and if I actually had to pay for my meal, I would probably have given it 1 star instead of 2.
Before you read further, you should know that all seven of us have seasoned palates for Japanese food and can definitely spot authentic well made Japanese dishes when we see them. I am in no way an elitist when it comes to Japanese cuisine, but for the prices that Koi charges, quality is expected. Simply put, you can find a meal of equivalent quality with better taste and half the price in one of the hole in the wall teriyaki shops in the university district.
On to the food. Tell tale signs of a bad Japanese restaurant come from the basics. If they cannot make basic staples of Japanese food correctly, you know you have found either a bad Japanese restaurants, or one made for gai jins. I found the miso soup at koi to be tasteless, and to make matters worse, the green tea was WAY too strong. It felt like they left the leaves in there to soak overnight. The very act of messing up things so simple speaks volumes as to the competency of staff. Additionally the servers completely neglected to give us tempura sauce or katsu sauce.
The chicken katsu and fried soft shell crab appetizer were overbreaded to the point that most of us had sore throats after eating here. Our california rolls were far warmer than room temperature and they looked messy in appearance. Taste wise they were average. The spider roll on the other hand, had way too much rice. The rice was piled on so much that it was literally all we could taste. I will concede that the caterpillar role was decent in both presentation as well as flavor, if as much time and thought was spent on the other dishes this review would be a praising rather than a critique. One of us ordered a donburi that resembled a stew more than a rice dish and the sashimi that we ordered was edible, but definitely nothing to write home about. The salmon nigiri lacked any sort of marbling and the maguro had no substance to it.
There is a reason why you do not see any Japanese people dining at Koi, this if anything, is the most reliable indicator of quality. If you can accept bad food in place for exceptional ambiance, then you might consider Koi. However, if you cannot stomach bastardized Japanese food at high prices, then avoid Koi like the plague. You would be much better off at Fuji in the International District, either I Love Sushi location, or Shiki in Seattle.