At any rate, perhaps the skills of the glassblowers were indeed a factor in the problems with making sheet glass? From what I've read, it seems like until about 1870 most blown articles were small, thin and fragile.
Just so I'm understanding things correctly, was the method of making sheet glass at the time that of blowing huge bubbles, slicing them open and laying them flat?
The process of sheet glass manufacture involves blowing a large gob of glass into a sphere, then swinging the ponty rod to expand these into cylinders, cutting the ends off to create a tube, cutting down the inside centre of the tube, reheating the tube to a precise temperature (too much and it sags), opening and flattening the tube onto a table, then annealing. Assuming glass blowing is already a mastered skill, then the only part likely to have caused the men a problem is the swinging, but this is unlikely. Whether there was some other problem with the production process I cannot say.
BTW, the traditional cutting method was using iron bars and abrasives. Can you expand on this? I'm trying to picture how this worked. Were the bars and abrasives two separate methods, or used together? I saw a reference to early diamond point engraving, and wheel cutting was used by the late Edo period. Maybe bars and abrasives refers to diamond point (or "scratch," since diamonds weren't always used), and the abrasives were embedded in the bars.
I have no idea, and was merely quoting Akiko's article. I imagine the bars were used along the length in a sawing fashion, with abrasives (as a paste?) to aid the cutting. Obviously a far longer and laborious method.
I presume Akiko is aware of
Blair, Dorothy (1973), "History of Glass in Japan": 479 pages 240 b/w 37 colour.
I would assume so - she is a lecturer at Tokai University so one would expect this to be available to her. But thanks, I will mention it.