Kachi Katchin (カチカッチン鋼 Kachi Kattchin Kō) is a material, it is a more durable variant of Katchin.
It was said by Great Priest that Kachi Katchin is even stronger than Universe 7's Katchin and was used to create the arena for the Tournament of Power. It is presumably the hardest material in the multiverse. However when Iwne, Liquiir, and Arack (Gods of Destruction) did battle they have little trouble breaking the arena both with the shockwaves emanating from their physical and ki attacks colliding.
- Despite being the hardest material in the multiverse, it has been broken on more than one occasion. Once by Iwne, Liquiir, and Arack's practice match, and again by Goku and Vegeta's combined Final Kamehameha against the Trio De Dangers. Kale even destroyed the ground around her just by shouting.