持国天・増長天・広目天と並ぶ四天王の一尊である武神、毘沙門天の甲冑の文様に使われた ことからこの名が付いた、3つの亀甲を山の形に組み合わせ連続させた文様。モチーフが隙間なく配されたものだけでなく、互い違いに配されたものも見られます。

The pattern you're describing is known as "Yoroi-kikkō" (鎧亀甲), named after the armor of Bishamonten, one of the Four Heavenly Kings and a warrior deity in Japanese Buddhism. It features three tortoise shells arranged in a mountainous pattern. This motif is not only seen in a tightly packed arrangement but also in an alternating pattern with gaps between them.

Obi fabrics with this Japanese pattern from the obico selection