evidence: Tensions have flashed numerous times over the Senkaku Islands, which China calls Diaoyu Islands, including face-offs between Japanese and Chinese warplanes and ships. [...] China says its claim to the islands extend back to 1400s, when it was used as a staging point for Chinese fisherman. [...] Since then, the US has stated ownership of the Senkaku/Diaoyu Islands is a matter between China and Japan, but, under treaty obligations, the US says it would defend the islands because they are administered by Japan.