Name: 黒麹極一滴 Kurokōji Kyoku Itteki
Type: さつま芋 Sweet Potato shōchū

Potato: 黄金千貫 Kogane Sengen
Ingredients: さつま芋、米黒麹 Sweet Potato, Black Rice Koji
Alcohol: 25%
Distillery: 常楽酒造 Joraku Shuzo
​Address: 2577-13 Takeshi, Nishiki-cho, Kuma-gun, Kumamoto
Website: https://joraku.co.jp/

Additional Content: Great explanation of the techniques used to produce Joraku's rice, wheat and potato shōchū, its only in Japanese but translates well with the auto-translation feature on google.
https://joraku.co.jp/brewing

About: Kurokōji Kyoku Itteki
Koichi Kuraza (Chief brewer), this shochu is made using traditional manufacturing techniques, using domestic potatoes (Kogane Sengan) grown in fertile soil, combining good water and good koji. Black malted rice and atmospheric distillation create an exquisite harmony of sweet potato flavor and refined sweetness. 

In the bottle: The initial aroma of this shōchū is really smooth and enjoyable with hints of potato and a general sweetness, however, must like the taste it does not linger very long.

On the rocks: A nice and smooth potato shōchū flavor dominates at first and then the sweetness that comes from the black koji comes in, however, it mellows really quickly.

Straight: This is a really mellow shōchū, enjoying this neat in the glass definitely keeps the flavors front and center, with a nice sweetness that pleasantly lingers.

水割り Diluted with water

4:1, 3:2, 2:3 ratio: Unfortunately, this shōchū does not hold up when diluted, especial at the higher ratios, while not bad, it does lose the majority of that potato shōchū taste.