Due to the gracious generosity of an FPN member I received a lovely sample of the Bungbox Ink of Witch by Sailor. This is a special ink made for a pen/ink/stationary shop in Japan. Sailor does this a lot for the shops in Japan, often promoting colors related to the history or geography of the city where the shop resides.
The ink is quite interesting, a velvety black that can sometimes appear deep dark muted purple. The scans of writing for this ink found online indicate that it is more purple than black, but with this sample, in my pens, that's not the case. It's still a very good, very wet ink.
I'll post the chroma test later whan it dries. Mostly it looks like it'll be black with a bit of purple (surprise!).
How to obtain this ink? I'm a little unsure. There's an ebay vendor cool-japan that can get many of the specialty inks. I'd seen a post mentioning that Bungbox will ship to US, so with some help from google translate you could visit the Japanese website. But I know some colors you might need to order twelve at a time. This could be one of them. If so, maybe there'll be a group purchase at some point.
I've read that the ink shows it's purple side more with fine nibs. I haven't tried that at this point.
On inkjet paper, scan.
On laserjet paper, scan.
On moleskine, scan.
On Mohawk via Linen paper, iPhone photo, so probably darker than in reality.
Waterproof tests. The ink is quite waterproof. You might loose the purple, but the black stays.