The doukake is the decorative protective cover that sits on top of your shamisen’s sound box to protect your instrument’s skin.
Doukake come in many fantastic designs. They also come in many different sizes. As shamisen are often adjusted to fit their player’s body, there are many different dou sizes. To estimate wether a doukake will fit, it’s a good idea to measure the dou’s long side and its height.
The dou’s height corresponds with the doukake’s width.
The dou’s length from corner to corner corresponds with the doukake’s length.
It’s not always easy to find a snugly fitting doukake for your instrument.
I do not recommend getting a too small doukake. It will probably slip around and will make playing less comfortable. If the doukake is just slightly too large, you can stuff it out with some rubbery fabric.