This is the opening salvo in the anago (conger) kaiseki meal served at Ikku in Yanaka: otsukuri (sashimi), with negi scallions, fresh-grated wasabi root and akajiso sprouts.
Eel presented with as much care and precision as you'd find at a top fugu restaurant, and served with a dip of citrus-tinged shoyu.
Remarkable. And beautiful.
With a bit of persistence (and a good detailed map), you'll find Ikku hidden away in the atmospheric backstreets of Yanaka, a short walk from either Sendagi or Nishi-Nippori stations.
It has no web site; it looks very simple and plain; you can't just drop in (you have to book two days in advance; and it's quite unique.
More details (in Japanese) here…