CHAT with Noriyoshi Nagai, the youthful sixth-generation owner of Nagai Sake, and you will learn a couple of things about him. First, it is obvious that he is deeply passionate about developing new forms of sake.
Second, and only if you have been sufficiently nosey, is that his ancestor - the first-generation sake brewery owner - was a samurai.
Unless you are a teetotal ninja, both facts should impress you, especially when you also discover that Mr Nagai is focused on matching sake and food.
Nagai Sake is located in Gunma prefecture's Kawaba village, about 170 km north-west of Tokyo.
It produces three premium sake brands - Tanigawadake, Mizubasho and Nagai Style - with the last one a super-premium Mizubasho that is aged.
Sake may be called rice wine but unlike wine, it is brewed, which means sake is drunk fresh or within a year.
But inspired by French wine, Mr Nagai has created sparkling, vintage and dessert sakes. It all started when as a 26-year-old in 1988, he sipped a glass of Puligny-Montrachet. He recalls: "I had no previous experience of wine but it tasted perfect."
At the time, he was learning about sake-making, so he wondered if he could combine both.
So from 1995, over a decade of experimentation with wine maturation techniques, he duly arrived at the importance of temperature.
"The same sake stored at a different temperature has a different taste," says Mr Nagai, adding that minus two degrees is ideal when cellaring for 10 years. "For 20 years, it has to be minus five."
He also realised that for the best results, vintage sake has to be kept for at least 10 years, with 12 being the average. Dessert sake, on the other hand, is aged for five years.
His sparkling sake is called Mizubasho Pure and it is junmai daiginjo processed the traditional methode champenoise way like champagne, with a secondary fermentation in the bottle.
The only difference is that there is no disgorgement because no dosage is added. The first Pure was released in 2008 - after five years and 700 tests (that is, 700 broken bottles) to recreate the same pressure in the bottle as champagne.
So what is the motivation behind this new Mizubasho type of sake?
"All sakes smell of rice, which is the old style. But Nagai Style is light, just like wine."
Style, old or new, probably wasn't on founder Shoji Nagai's mind when the ex-samurai moved from Nagano to Kawaba during the Meiji period to set up his brewery amid lush forests and flowing rivers. Kawaba is named for the confluence of five rivers and there is an abundance of pristine water in Gunma (the prefecture supplies about three-quarters of Tokyo's H2O needs).
The water for Nagai Sake originates from the top of Mount Hotaka, one of more than a dozen mountains in Gunma, and it is soft and mildly sweet. It starts off as snow and rainfall, percolating more than six decades through the rock and soil before it is pumped out from 60 metres below the ground and used to wash and brew the rice (the same water also flows out of the restroom taps because not doing so would complicate the plumbing).
To protect this precious resource, the Nagai family bought up 50 ha of surrounding forest.
Even though Mr Nagai knew he was groomed to take over the business, he studied architecture in university. He does not see a contradiction because "architecture is art plus design, just like sake making", and sake making requires waza - a combination of technique and art.
In addition to designing a new brewery building and the restaurant next door, Mr Nagai has also applied waza to modernising and automating brewery operations.
But he emphasises that what remains unchanged is the traditional use of the five senses in making sake.
"We still feel the moisture of the steamed rice, look at the change in the yeast, smell and taste the fermentation, and listen to the bubbles in the moromi (fermenting mash). Man makes sake, the machine is only a tool."
His samurai ancestor would be proud of him.