It's very difficult to source truly delicious sparkling sake, in fact almost none of it is exported. As long as that's the case, rather than compromising with sugary-sweet, soda-like sake, I recommend the original and the best: champagne.
Champagne has more in common with sake than any other drink. Both beverages feature a beautiful harmony of sweet and savory flavors: umami, nutty, pastry, fruity and floral, all coming together like a symphony, and pairing impeccably with food.
For the Sunflower collection, I'm focusing on umami-driven, sake-like champagne, as well as small special releases. You'll also occasionally find some sparkling sake in here-- but only the best, good enough for the most important celebratory toast.