kezuribushi, kezurikatsuo, hanakatsuo, shaved skipjack, shaved bonito.
This is a basic ingredient in the Japanese kitchen made from dried bonito (skipjack tuna) which is a fish prized for its high concentration of umami compounds. By drying it, the level of umami is further concentrated, making katsuobushi a core component of most Japanese stocks (dashi)
What's it taste like?
Since it's dried and shaved very thin, it has an almost paper-like consistency, but as it meats your tongue, it explodes with an intense smoky flavour that almost tastes like you're sucking on a bouillon cube. If you've ever had miso soup before, you'll recognize the flavour since miso soup is made using stock extracted from katsuobushi. Unfortunately the art of making dashi from katsuobushi is dying as most people opt for the more convenient "instant" dashi powders which are loaded with MSG.
Where do I get it?
Katsuobushi should be available at any Japanese grocery store and may be found in the "Asian" section at major supermarkets. They either come in big plastic bags, or in smaller bags which contain small serving sized packets.
When is it best?
Since it's a dried food, there is no season, however you want to make sure it's not past its expiry date as the flavour diminishes as it gets older.
How do I use it?
Katsuobushi comes in a few different thicknesses. The thick ones are used for making dashi (Japanese stock), while the thinner ones can be used as a topping for various dishes including okonomiyaki and oshitashi. When mixed with soy sauce, it's called okaka and is a common filling in onigiri (rice balls)
Some studies have shown that when katsuobushi interacts with certain enzymes an oligopeptide is produced that lowers blood pressure.