In the tea ceremony, there is a form of “nodate,” or outdoor tea ceremony, in which matcha is prepared and enjoyed outdoors.
Such a nodate is actually a little different from the tea utensils used inside a tea room.
This is because inside a tea room there is a mizuya, and once tea is served, it can be put away in a procedural manner, but outside it is different.
After tea is served outside, the tea utensils need to be brought back to the tea room safely.
One of the things that have been developed for this purpose is the chasen, a tea whisk for nodate.
The size of the Chasen for Nodate is slightly different from the one used in the tea ceremony room.
One of the characteristics is that it is a little smaller and wider. The reason for this is to make the size as compact as possible for easy carrying.
As a slightly clearer example, here is a mini-sized, field-use tea whisk.