In-Depth: The Grand Seiko T0 Constant Force Concept Tourbillon, The First Tourbillon Movement From Grand Seiko Grand Seiko’s new concept tourbillon is its first tourbillon, and its first constant-force caliber as well. Continue reading ‘In-Depth: The Grand Seiko T0 Constant Force Concept Tourbillon, The First Tourbillon Movement From Grand Seiko’ 0 Posted In: Uncategorized