The arrows indicate the direction the fibres align |
In practical terms this can be used to advantage. The paper hinges on Japanese screens for example must be cut so that the fibres run across the hinge so as to utilise the paper in its strongest direction. In pasting or dying paper the majority of the brush strokes should be along the fibre direction as brushing hard across the fibres will weaken the paper more quickly and cause the fibres to roll .
On the hand scrolls the fibre direction must be switched between the layers of paper so that the scroll will both roll smoothly but remain flat when opened.