That’s Iroshizuku Fuyu-gaki on Rhodia 80 g. paper. This is my fifth Iroshizuku ink review and I’ve been entirely disappointed with four of them. The fifth, which I liked enough to buy despite its quirks, is Ku-jaku.
Someone talk me out of hating this ridiculously poorly behaved ink that goes for $0.56 per milliliter. I won’t judge the entire line on the five I’ve tried, but I’m not wasting any more money on any more of this brand.