The Wine What site has an article on a style of sake more commonly found in the wine world - rosé.
Although sparkling sake - also called awazake - has become more common in recent years, Takizawa Shuzō are taking a different inspiration from the wine world with a clear pink sake made sparkling by secondary in-bottle fermentation. No colour is added - it all comes from the yeast.
Reporter Kaori Isono discovered the unusual sake during a bus tour of breweries in Saitama, which is currently in fourth position in the ranking of sake-producing prefectures in Japan (by volume). Takizawa Shuzō is in Fukaya City, best known for its onions and red brick buildings [relatively rare in Japan].
Founded in 1864 in nearby Ogawa, the company sought access to land and water and set up a brewery at the Fukaya station of the Nakasendo road in 1900. It was and still is famous for its 20 metre red brick chimney.
Kuramoto-tōji Hideyuki Takizawa set himself the challenge of producing a clear sake with bubbles that rise in a straight line - also used as the name of their sparkling sake label, "Hitosuji" (ひとすじ, "straight line"). It's recognised as a sparkling sake under the stringent requirements of the Japan Awasake Association. Sediment is collected in the neck of the bottle in a process similar to remuage in champagne production, followed by freezing the neck and disgorging.
Unlike champagne, no additional source of sugar (dosage) can be added for secondary fermentation, otherwise the product no longer qualifies as sake under Japanese law. No sake-specific rice is particularly suited to making sparkling sake, but the brewery uses the Saitama sake-specific variety Sakemusashi, or Gohyakumangoku which was recently recognised as a sake-specific rice in Saitama. The result is a clear, sparkling junmai with refined sweetness and acidity plus a tight mouthfeel that complements both Japanese and Western food.
November 2018 saw the launch of their new pink sparkling sake, Hitosuji Rosé. The label and gift box have a feminine design with the hiragana character for "hi" written large in silver. The reporter tried it and noted a sweet-but-tart flavour reminiscent of strawberries, refined if rather sweet. She thinks it would do best as an aperitif or served with dessert. Particularly paired with strawberry shortcake!
The flavour and colour both come from yeast, namely aka-iro kobō (赤色酵母, "red yeast"). [Which seems to be Xanthophyllomyces dendrorhous.] This is a recognised sake yeast, but one that is incapable of making the nucleic acid adenine itself. It's hard to use as it needs a source of adenine and ferments weakly. The yeast itself turns red, making the sake appear the same colour, but when the sake is clarified and separated from the lees the pink tint the brewery worked so hard to achieve is lost. Previous pink sake has used red rice, or if they did use "red yeast" the best they could do was a pale pink nigori.
That's what made this clear pink sparkling sake so hard to develop, with separation from the lees being the most difficult part. Surprisingly, Takizawa confessed that the development of the original Hitosuji had actually taken far longer.
If you're interested in this "red yeast" I can highly recommend Kamoizumi's low-alcohol rosé sake, Cokun!