IWA 5 is a Japanese sake producer that creates premium junmai daiginjo sake using traditional brewing methods. The brand focuses on assemblage-style sake production, which involves blending different sake components to achieve complex flavor profiles, similar to the blending techniques used in Champagne production.

The producer's approach emphasizes precision and craftsmanship in creating junmai daiginjo, one of sake's highest quality categories. Junmai daiginjo requires rice to be polished to at least 50% of its original size, removing outer layers to expose the starch-rich core that produces the cleanest, most refined flavors. This intensive process results in sake with delicate, nuanced characteristics and exceptional clarity.

Their current offering, Assemblage 4, represents the fourth iteration of their signature blended sake, demonstrating the producer's commitment to consistency while allowing for subtle variations that reflect each batch's unique qualities. The assemblage method allows for greater complexity and balance than single-tank productions typically achieve.