Of course, the tuna featured is from Yamayuki, which seems to dominate all but a few of the top-ranked tabelog sushiya these days. Setoro and belly chutoro are the first nigiri served, followed later in the course by chiaigishi and otoro. The flavor is exceptionally "meaty" and clean, with strong mineral taste. I can't claim to know whether this flavor and texture profile this was a conscious choice, or just the product on this particular day, but I did find it uniquely delicious and exceptional.