I had a couple woodcased Nano Dia 2B and was wanting to review them, but when I went looking around for info online, I found they had some Bs, but also a whole line of mechanical pencil leads. Went digging deeper and found that they made the leads first and the woodcased were something that came after. I imagine these work well with the Uni Kuru Toga, but I can't stand the looks of that pencil, and haven't ever felt the need to buy one, since I rarely use a mechanical anyway.
I ordered the Bs and the pencil lead in 0.9mm B as well. I like a thick mechanical lead, and have a Pentel P209 0.9mm for testing.
These come in 3 different colors, light blue, light green, or light pink. They are essentially white pencils with a different accent color. The color denotes nothing, it is just a style choice. The pencils are a soft hex, but not quite semi-hex territory. There is no eraser and they are unfinished on the ends. These feel like an entry level pencil that has some quality. They are marketed as "for kids" in Japan. They look like they could be wrapped, as there is a little bit where the design doesn't match up, but I think they are actually painted by rotating the pencil. I'm just guessing here, but if it is a wrap job, it's the best damn wrap job I've seen.
So the thing that's so special about these pencils is the nano-carbon added to the lead to allow for the darkness to still be there, but harden the lead up, which would be good for kids who have a bit of a heavy hand when learning to write. Tiny diamonds in the pencil! Diamond dust, more than likely. In my tests, all the cores performed wonderfully. I personally liked the woodcased B the best, but all were great. Smooth, with good point durability on the Rhodia Graph paper I used to test. Smudging was decent, the B performed pretty well for a writer. When you start to get to drawing pencil grades, you want the smudging, obviously, so the 2B smudged as to be expected. The mechanical B was a bit lighter than the woodcased B, had a little more gray in it. They all erased beautifully. The woodcased don't have an eraser (or even an end-dip) so I used the Seed Radar plastic eraser, which worked wonders.
Overall, I'm on the fence about these pencils. They are good pencils and great cores. But I can't get over the way they look. I wish this graphite core was available in another form from Mitsubishi, then it would end up being one of my favorite pencils. I may end up using these for bullet pencils. I am, however, very happy with the mechanical pencil lead, and can see this being my go-to lead moving forward.