The Chasen Holder is an essential item to keep longer the Chasen shape. Actually after long time usage the hosaki (the tiny bambou strips composing the wisk) can loose their shape or get damaged. This can happen also if the wisk is not well dried after usage.
Therefore it is important to wash the Chasen with warm water after use, and the place it up side down on the Chasen Holder.
This will allow it to keep its shape for a longer time.