For another view, see Michael Anderson's three articles on sumitsuki in issues 26, 28 & 29 in Timber Framing (also in the Guild's Joinery & Design Workbook, Vol. 2, I think.

Here's a short passage:

"JAPANESE layout has used the center line, square rule method since hundreds of years before
industry arrived along with Admiral Perry’s
black ships. The method, historically as well as
in present-day Japan, seems to have been little
affected by whether regular or irregular timbers
were employed. In fact, in pre-industrial
times, one of the advantages of employing a
method based on vertical and horizontal center
lines was the ability to use less expensive
unshaped material wherever possible. The same
layout techniques are as useful for marking
precisely-dimensioned timbers as for the rough
logs of the koyabari roof framing, though the
latter require additional techniques.
Even the old farmhouses or minka, famous
for their irregular spans and timber dimensions,
were laid out according to square rule.
There is another reason why a scribe method
was and is used only in special situations in
Japan. Japan is a small country. The houses are
small, the cars are small, the builder’s yards are
small. Nearby where I live on a well-traveled
road, there is a patch of ground with a lean-to
roof over it some 8 ft. deep by 20 ft. long. In
this small space a single carpenter, working
alone, manages to mark and cut the entire
frame. There simply is no space to maneuver."