Authentic Japanse stewed fish head or "kabutoni" 兜煮 traditionally starts with an uncooked fish head which is split in half (called "nashiwari" 梨割り) before stewing. Since we needed the head to properly display the whole grilled red fish, this fish head was already grilled (and even hot smoked). In addition, the head was really big with its thick skull and sturdy cervical vertebrae preventing me from cutting it in half short of using a reciprocal saw.
So, by no means, this was "kabuto-ni" but "kabutonioid" 兜煮もどき. Besides getting a fish head, one of the problems of "kabutoni" is the presentation. This one is particularly not good. It almost looks like a mummified fish head (below) dug up from one of the Egyptian pyramids. In any case, I just simmered the grilled (hot smoked) head with dashi, mirin and soy sauce with slices of ginger. The traditional way is to place the burdock root or "gobou" 牛蒡 in the bottom of the pan and then place the fish head on top but I did not have gobou. I just placed the fish head in the pot and added daikon instead.
With an "otoshi buta" 落とし蓋, I simmered it for 40 minutes or so and let it cool down. I actually served this the next day after it spent the night in the refrigerator and warmed it up the next evening.
The result? Obviously not as good and real kabutoni but it had lots of meat which is a bit on the dry side but not too bad. The skin was not edible (like leather)(but neither was the skin on the rest of the fish edible). The gelatinous stuff behind the eyeballs, which connoisseurs of fish head including myself love, was not as gelatinous but was quite good (my wife graciously offered her share of the eyeballs to me). Next time, we will get a smaller red snapper and may try different dishes from the fillets and maybe a more authentic "kabutoni".