Bud pinching takes place between spring and summer. Bonsai artists will remove the ends of new soft buds growing during this time by pinching them off.
This is done to prevent the branches from growing too much and it will allow more delicate branches to grow. Through bud pinching, the tree may also grow with smaller leaves, which is important for the bonsai to feel like it scales correctly.

Bud pinching will take place between spring and summer. Bonsai artists will remove the ends of new soft buds growing during this time by pinching them off. This will make the branches and the leaves smaller and feel neater overall.
For trees in the cypress family like junipers and cedars, you will pinch off any new buds which break the shape of the tree.
For pine bonsai such as the Japanese white pine and Japanese black pine, new buds are only pinched off halfway. Artists will allow them to grow out in a balanced away.

Defoliation involves cutting off leaves that are either too big or reducing the number of leaves in certain areas of the tree.
Bud pruning involves cutting off any buds which have grown too long or are unneeded.
For leaf pruning, the artist will cut off parts of large leaves on deciduous bonsai.
All of these jobs are done to give the tree better access to sunlight and wind and to achieve a more balanced appearance for the bonsai.