The first time I encountered one of the violas of Hiroshi Iizuka (those are 2 'i's) was at the age of 10, when my mother and I met with Michael Tree - the violist of the Guarneri Quartet. Since then I found out that so many violists, whos playing I love, play on his instruments.
One of the problems of building a viola, is that the relationship between it's size and range is usually not correct, and therefore the viola is often weak compared to a violin or a cello. If one were to build a viola sized based on it's relative range between a violin and a cello, it would be too big to play. In fact, many of the most famous violas built in the 16th century (by Gaspar de Salo for example) were built so large, that violin makers in the 19th century trimmed them down to a manegable size, and often destroyed their sound.
Hiroshi has been experimenting with violas of unorthodox shapes for many years, and has come up with a few different models that maximize the viola's body size, without making the instrument difficult to play. He is originally from Japan, and has been working outside Philadelphia for a few decades now.
When I moved to Berlin and studied with Wilfried Strehle, I fell in love with his Iizuka viola. The next time I was in Phladelphia, I visited Hiroshi, and asked him to build another one exacly like Wifried's. 2 years later, I was ecstatic to discover that Hiroshi has built one of his best violas in my opinion, and it was all mine.