Well, maybe I've made a mistake and presumed that two Americanisms, the sack suit (no front darts) and the tree button, roll lapel roll suit always come together like a pair of Siamese twins. They do in the case of Brook Brothers, (every sack suit will have 3 button roll lapel) but not with the Andover shop. And there are plenty of American suits with roll lapel and front darts around. Both styles, just like saddle oxfords, are uniquely American (and if Kiton makes a roll lapel it will be for US export); they are not worn anywhere else in the world. But then I am not the only one who presumes these two features to come together hand in hand like tweedledum and tweedledee. Here is an example from a Japanese site: http://www.geocities.co.jp/Stylish/7785/sac-suit_01.htm
The suit in question has a roll lapel, but as one can see in the second picture, there are definitely front darts. But still they call it a sac suit.
Hmm. In modern viewing, one almost always sees the sack suit (as offered by Brooks, Oxxford, Hickey-Freeman, etc.) to be a low-stance two-button, although historically it was a three-button suit. But roll-lapels are hardly unique there. While I did buy the Kiton mentioned in the US, I've bought many more jackets in this topology on the Continent, from marques ranging from Knize to Kilgours, from Ferragamo to Hermes. Peace, JG