Junmai Daiginjo (純米大吟醸) is the highest grade of sake.
To qualify as Junmai Daiginjo, sake must be made with rice polished to half of its original weight with a minimum of 50% rice polishing and 50% remaining.
But that standard is often surpassed by brewers looking to push the rice milling envelope that results in sakes that can be milled down to 35% down to 23% and even 7% remaining figures.
Junmai Daiginjo is extremely labor-intensive to brew. Due to the stringent quality controls involved, and the costs of the production process, it is produced only in very small quantities.
It is highly fragrant and complex in style, and its delicacy requires similarly delicate food matches like sashimi.