A matcha whisk(Chasen) is a bamboo whisk used to mix powdered green tea (matcha), in the Japanese Tea Ceremony. It is carved from one single piece of bamboo.
Place in hot water for a few minutes, before you use it the first time,
Dampen it before every use to prevent damaging the strings. The strings are the whisk's individual whiskers or bristles or prongs.
To clean your whisk, carefully rinse it under running water. You can use your fingers to gently remove stuck on matcha. Do not let the whisk sit in water. Do not use a dishwasher, or dish soap.
Store your whisk on a whisk holder (Kusenaoshi) to keep its shape or at least, bristles pointed up, like in the picture. Storage it in a too warm, or too dry place can cause the bamboo to split.
Improper storage can ruin the whisk's shape. To reshape it, dampen it in running water and gently unfold it using your fingers. Do not do this while the whisk is dry.
How long your whisk lasts depends on how you handle it and how much you use it. When the ends of the bristles start to break off, buy a new one because you don't want them to break off while you are preparing matcha.
Watching the videos below will help you appreciate the effort used to create each whisk.