Masculine or feminine
The first thing you must do is to decide if your tree is masculine or feminine. Usually, a tree is a mix of both and question is which sex is the dominant. This is absolutely crucial and perhaps the most important rule in choosing a pot. Some attributes that can help you along the way is that the curves, grace, smooth bark and sparse branches is considered feminine. The corresponding masculine traits are strength, old bark, deadwood, thick trunk and dense branches.
As a rule of thumb, the pot should be of the same height as the trunk is wide above the surface roots (Nebari). Pot length should be between 1/3 or 2/3 the height of your bonsai
Keshitsubo (height: 3 - 8 cm)
Shito (height: 5 - 10 cm)
Mame (height: 5 - 15 cm)
Shohin (height: 12 - 20 cm)
Komono (height: 15 - 25 cm)
Katade-mochi (height: 25 - 46 cm)
Chui/Chunono (height: 41 - 91 cm)
Hachi-uye (height: 102 - 152 cm)
Imperial (height: 152 - 203 cm)
The pots design should match the degree of masculinity or femininity of your tree. The closer you get, the more harmonious the experience of your final Bonsai.
Generally masculine pots are deep, angular, have clean lines and stout feet. A lip on the rim strengthens the masculinity, an inward rhyme reinforces the pot femininity. Feminine pots often have soft lines, delicate feet and are relatively low and sleek. Round pots, drum pots are generally considered to be androgynous.
The most general rule when it comes to choosing the glaze for a pot is that the color should appear in the tree, either in the bark, the color of the leaves, and fruit or flowers. Therefore, the unglazed brown, gray and earth tones are usually safe choices. They also provide warmth and stability to the Bonsai tree. But you can also work with contrasting colors like blue or cool green. They provide balance and refreshes the composit
Live long and prosper.