Hama yumi is a type of traditional Japanese bow made out of bamboo. It's used for archery, which is a sport where people shoot arrows at targets.
Imagine a really, really long stick that's curved in the middle, like a banana. This stick is made out of bamboo, which is a type of plant that grows really tall and straight.
To use the hama yumi, you need to hold it with both hands, and use your fingers to pull back on a special string that's attached to the bow. This creates tension, like a rubber band stretching.
Then, you take an arrow (a long, skinny stick with a pointy end) and position it so that it's resting on the bow. When you let go of the string, it snaps back into place and launches the arrow forward.
People have been using hama yumi bows for thousands of years in Japan, both for hunting and for competitions. They're very beautiful and elegant, and take a lot of skill to use properly.