Thicker sticks. Coating on the outside of the chalk. Different formulation to make it smoother and less dusty.
Basically, the chalk seems to be optimized for writing Kanji strokes which need to vary in thickness and weight.
And, yes, he did miss the boat in the US. I have never heard of this stuff before they went under (not completely true: my Japanese teacher complained about the quality of American chalk all the time--I should have twigged in). I would have bought crates of this stuff when I was teaching.
Hopefully the Korean company he sold the machines to won't be quite so insular.
Basically, the chalk seems to be optimized for writing Kanji strokes which need to vary in thickness and weight.
And, yes, he did miss the boat in the US. I have never heard of this stuff before they went under (not completely true: my Japanese teacher complained about the quality of American chalk all the time--I should have twigged in). I would have bought crates of this stuff when I was teaching.
Hopefully the Korean company he sold the machines to won't be quite so insular.