I bought a sample of Take-Sumi to have in my stash of Iroshizuku inks for sake of completeness and to try them all at least once. I don’t write with black inks, but do have different samples, and I have to say that, for me, Aurora Black, is a true dark black with no undertones leaning cool or warm; Take-Sumi is more of a charcoal, a very dark grey, leaning slightly on the cool side, but definitely not black in less than a really wet pen.
If I squint, I see shading from grey to black in wider nibs with medium flow during normal writing; it is opaque with wet writers in thinner nibs. Take-Sumi is saturated and dries quickly. Flow and lubrication are good for a non-lubricated ink! Dark reddish sheen in heavily saturated areas where the ink pools is visible, but not during normal writing with my pen and paper combos.
It’s flawless in all the pens in which I’ve tried it, and plays well with my dry Sailor 1911S 21 kt H-M. If I could only write with this pen, I’d be OK with inking it up with Take-Sumi; I still wouldn’t like the colour, but I’d enjoy the writing experience. Like I already wrote in a review or two, if an ink can make it in there (that particular H-M nib), it can make it anywhere!
It feathers and bleeds through on lesser quality paper, but on better papers, I’ve only noticed it feather on Oxford Optik—one might argue that this paper’s claim to fame is the ease with which handwritten notes get digitized, but I’ve had good experiences with other ink brands.