In this feat, Retsu Kaioh cracks a bell.
Average male height in China is 1.72m so i used that for one of the men near the bell. Info we have: Width of the cracks: 0.06m Total distance that was cracked: 11.46m Depth of the cracks: Who knows. At least 0.06m, but from the looks of it, the bell looks dummy thicc so i'll kick in a 0.3m of depth for it.
This states that: " Bells that are designed to ring or to play music are cast in a bronze alloy of approximately 77% copper and 23% tin. "
We know the fragmented area is 0.06 * 11.46 * 0.3 = 206280cc. Using the distinct fragmentation value of each material, we assume 158835.6cc is copper and 47444.4cc is tin. Fragmentation of cooper is 172.3 j/cc. Fragmentation of tin is around 132 j/cc.
158835.6 x 172.3 = 27367373.88J
47444.4 x 132 = 6262660.8J
27367373.88 + 6262660.8 = 33630034.68J = 0.00803 tons = 9-A
You can't separate an alloy like that. Just go straight for using the fragmentation energy of bronze.
Bronze has a starting shear strength of 297 MPa
Using the volume above...
206280*297= 61,265,160 J or 0.014642724665 tons of TNT = 9-A