These were the noodles.
They're ju-wari (十割 = 100 percent buckwheat flour) soba: delicate, refined and... remarkably green.
Made from freshly milled groats of shin-soba (new harvest buckwheat) grown in Gunma-ken...
Those on the right are from Fukushima-ken.
Placed side by side, you can see there's a distinct diffference.
Shibui indeed.
I'll drop a longer post on this place once I've tried more of their ippin ryori offerings.