Arrow fletching. Feather. The shape resembles the hawk or eagle feathers used in arrows.
The design is considered a lucky pattern since arrows aimed at a target (hopefully) do not return once shot. The design also symbolizes a straight path (in life) like the flight path of an arrow.
The yabane design is used both as a small and a large repeating pattern or as a standalone design element. Designs exist with all arrows facing the same direction or with arrows facing in opposite directions. In most cases, the design is displayed vertically but some designs also use individual scattered arrow shapes (at angles).
The yagasuri (矢絣, yabane kasuri) design is relatively easy to weave with identically kasuri (ikat) dyed threads since you just have to shift/lift the threads slightly in a mirrored angle to create the pattern.