The koma is essential as it’s the part which transfers the vibration from of the string to the skin, which broadcasts the sound you hear!
There are many types of koma to choose from, and they all produce subtle differences in tone. One isn’t necessarily better than another, so I’d recommend getting whichever you’re most attracted to and I’m sure it will be perfect for you. Over time, you can collect different koma as you seek to fine-tune your shamisen’s tone.
