Bonsai Kiryu

Japanese Kiryu is a common component in Japanese soil mixes.  Kiryu is a very dense pumice like substrate that does hold water, but not as well as it's pumice counterpart.  Kiryu is used as an alternative to lava that has a more uniform look in most mixes.  Kiryu is great for trees that will not be repotted for many years as it does not easily break down.