Hi Drew: This is what I understand from the 3 pumices (Kanuma, Akadama, and Satsuma). Mind you that there are also different qualities of the pumices.
Kanuma tsuchi (鹿沼土): regular kanuma, whitish brown looking. It is very soft, and absorbs the most water out of the 3 pumices.
Koushitsu Kanuma tsuchi (硬質鹿沼土): hard kanuma. It is treated wit high temp. Makes Kanuma harder and less likely to crumble. This is better quality Kanuma and it is much better for C. goeringii
Akadama tsuchi (赤玉土): regular Akadama, reddish brown looking. It is very soft, and has the most acidic pH out of the 3 pumices.
Yaki Akadama tsuchi (焼き赤玉土): baked, fired treated Akadama. It is treated with high temp. Makes akadama harder and less likely to crumble. This is better quality akadma and it is much better for C. goeringii.
Satsuma tsuchi (薩摩土・さつま土): whitish looking. It is hard. It has the poorest water rentention out of the 3 pumices. However, it is the most porous so it provides the aeration for C. goeringii's root system.
Lastly, there is another type of pumice called Karu-ishi(軽石): this is very light pumice and can be used and added into the C. goeringii potting mix if desire. This is volcanic in origin and it is very porous so good for the roots and drainage for C. goeringii.