These are the apex of Katsuobushi, a special fermented style made from poached and dried skipjack tuna which is smoked for about two weeks, which then goes through a six-month(!) multi-stage process of fermentation and sun drying. Finally, the dried tuna cuts are ready,  and are finely shaved. This kind specially fermented bonito is also known as karebushi. 

Karebushi has a softer, more sophisticated flavor, with less smokiness than its non-fermented counterpart. Typically, when Japanese chefs want more depth in aromatics and nuanced flavors, they go for karebushi. When they want more smoke and intensity, they'll go for the non-fermented katsuobushi. Want both depth and smoke? They'll use both! 

This thin-shaved style is great for making dashi, as well as a garnish on vegetables, or okonomiyaki. 

Made in Makurazaki, Kagoshima by Matoba Suisan.

Store at room temperature, away from direct sunlight. Keep refrigerated after opening for maximum freshness.