No matter what type of bonsai pot we choose, we should make sure that our bonsai pots have adequate drainage holes. Bonsai pots made in China and Japan usually have large drainage holes, so that excess water can drain away. Cover each drainage hole inside the bonsai pot with a piece of plastic drainage mesh to prevent any soil falling through the holes.
Some bonsai pots may have small holes around the side of the base. There holes can be very handy sometimes. We can use these holes to tie the bonsai tree into the pot, or tie a branch of the bonsai tree to a downward position for training. I also use these holes on my bonsai pots to tie and secure the pots on my bonsai rack.
Pots and containers are often available from garden centers that are massively produced, yet not necessarily for bonsai. Usually these pots and containers only have one small drainage hole, or sometimes, none at all. Do not try to use a pot with only one drainage hole, as drainage hole is a major factor in growing healthy bonsai trees, and one small drainage hole is definitely not enough.
In addition, we should also check if the base of the bonsai pot is flat so to make sure there is no area where water can become trapped and cause root rot.