Bonito is great fish! The Japanese name is KATSUO (KA-TSU-O).
The searing of the outside is not to make it cuttable, but that is actually a method of cooking. It's called TATAKI.
In Japan, katsuo is served either way, completely raw (sashimi), tataki or prepared-dried-then flaked (katsuo-bushi).
When served as sashimi or tataki, the common way is not wasabi, but actually grated ginger root (suri-shouga) and soy sauce. Mmmmm....
Katsuo-bushi (
http://en.wikipedia.org/wiki/Katsuobushi) is most commonly used as a base for broths for noodles (udon and soba) and soups. The flakes are also used to top off some other dishes, like a Japanese pancake (
http://en.wikipedia.org/wiki/Okonomiyaki).
If you are having problems cutting the katsuo, then it's time to break out the honing stone and sharpen that knife!! Or you forgot to bleed the fish!!
When you catch bonito, absolutely make sure to bleed the fish by cutting the artery by the gills and a cut at the base of the tail fin (I just cut the tail off). The meat of the bonito will taint with the blood and make to be a very mushy, very fishy and not so great. And if possible, put on ice as soon as possible. (I know, on cattleboats the best you can do is a gunny sack! Oh well.) I keep the cooler in my car, stop by a 7-11 and buy a bag of ice on the way home.