As Karen's post here states, this Whisk Keeper(Kusenaoshi) is critical to keep your Whisk (Chasen) in it's original shape and also clean.
I live right on the coast, in the southeast and mold here is bad. I used to keep an old Chinese-cheapo I had in its original tube (plastic) I bought it in. Big mistake! It molded and crinkled up.
After using the Chasen(whisk) I will rinse it in clear water and flick off any remaining water in the sink, then place it on here. Perfecto!
Keeps its shape and no mold! This Kusenaoshi(whisk keeper) helps your Chasen(whisk) to dry quicker also. Important is you use it everyday! I use two chop sticks, laid parallel, about an inch apart, to keep my Kusenaoshi open on the bottom so the Chasen can dry even quicker. The picture does not show it, but the Kusenaoshi is hollow, open at top and bottom.
Another Excellent product by Hibiki-An. Five Stars.