Recently I practiced repairing a tea cup with small clamps or 'kasugai'.
This technique has developed in China.
The picture below is a famous celadon bowl from Nansong dynasty China.
It is in the National Museum in Tokyo.
The original holder of the bowl is the Muromachi Government's shogun Ashikaga Yoshimasa
(足利義政: 1436-1490). At that time such Chinese ceramics were of particular value in Japan.
As the bowl had got a crack, Yoshimasa sent a messenger with the bowl to China to seek a similar one.
But in Ming dynasty China there was no similar bowl, the cracked bowl was repaired with kasugai and sent back to Yoshimasa.
However, Yoshimasa didn't like the way of repairing at all. It is said that it is when the kintsugi has begun to develop in Japan to repair broken ceramics more beautifully.