Assertion: narwhal's skin | /r/ObjectUse | used as under layer
Facets:
value: in japan
type: LOCATION
value: on japanese swords
type: LOCATION
value: sometimes
type: TEMPORAL
Source sentences:
text: In Japan, the skin is sometimes used as an under layer on Japanese swords due to its hard, rough, texture that keeps the layer on top from sliding on the handle during use.