Since creating a rising, belt-like pattern inside a dotaku reduced the abrasion caused when it was rung, the use of two lines forming rising patterns became an increasingly common style as development of the dotaku continued.
なお、銅鐸を「鳴らす」段階にあってはこの内面突帯の摩滅を軽減するため、この内面突帯を二本に増やした物が銅鐸の発達と共に増えていく。