high-grade katsuobushi (mold-cultured dried bonito)
Refers to the highest quality katsuobushi that has been repeatedly dried and fermented with mold (often Aspergillus glaucus), resulting in a deep flavor. Compare with 枯節 (karebushi), which is a broader term for mold-cultured katsuobushi; 本枯節 (honkarebushi) is a synonym.
See also: 枯節
At the traditional restaurant, they pride themselves on their ichiban-dashi made with high-grade mold-cultured katsuobushi.
Honkare is made with particular care even among mold-cultured katsuobushi.