The Old Shoe MB was bought secondhand and is clearly a blue-black, but looks blue in the bottle. I swear it does. It's there for...contrast. Yeah, that's it. Contrast. Just like the Rotring.
Tsuyu-Kusa, while a lovely color with excellent properties, seems a little pale for everyday use. Asa-Gao... just didn't thrill me.
My favorites? The classic Waterman Florida Blue, now a collector's item. And JH Eclat de Saphir. If I wanted a darker blue, Myosotis. I guess Skrip is up there, too, rating an Okay, At Least It's Inexpensive (this would be the conical-bottle Slovenia version).
These are not my finest chromas; I plead InCoSomNia.
Are my ink-bottle days behind me? Maybe. If Sailor made a true, clear blue with no green, turquoise or POIPLE undertones, I might be interested.