Well, Diaoyu and Senkaku mean the same things, in different languages. Senkaku is Japanese and Diaoyu is Chinese for (wait for it...) a group of islands!
Geography
Here's a map for those of you not intimately familiar with East Asian geography.
As you can see, the islands are in-between China, Japan, and Taiwan, due west of Okinawa, and for those of you who still haven't got your bearings, due north of the southwest end of the Ryukyu Islands. Helpful right?
The ownership of these islands has been disputed (primarily between China and Japan, but also Taiwan, ironically itself a disputed island) for a long time (going on 40 years), and this territorial dispute has been a source of tension in the alliance.
A Dispute
Recently, tensions have flared up, because of the arrest of a Chinese fishing boat captain by Japanese coast guard ships after the fisherman collided with the Japanese ships. If you're less familiar with the dispute, here is an excellent summary.
The discussion of the implications surrounding the incident has been pretty interesting. Initially, many writers, (primarily right-wingers) thought the incident would increase US power in the region, as Japan and other countries realized they needed each other and the US to check back an aggressive China. To some extent, this has been the case, as countries have grown more wary of China. Yet at the same time, China has rejected the US offer to act as mediator, denying the US credibility as a peacemaker, showing China isn't willing to cede that much ground, even if other countries turn to the US to balance China.
I've taken it upon myself to find various solutions and resolutions to the problem. For those of you who didn't click the links, neither Japan nor China have given up their claim to the territory, and offer the same solution: the islands are theirs. The populations of the countries feel the same way, which has only furthered the problem in the form of numerous protests and spilled over to affect diplomacy by creating tensions.
About the Words
Now back to our word(s). Senkaku, Diaoyu? Does it make a difference? It is probably telling that the members of the media (see links above) all refer to the islands by both names when reporting the dispute, unless they are being blatantly partisan. Each name represents a side on the issue, a stance on which country the territory rightfully belongs to. If Obama were to come out and say "The Diaoyu islands belong to China," it would be a lot more powerful than, "The Senkaku islands belong to China." The second, in fact, would be pretty confusing. This demonstrates the surprising power words and names have in shaping current events. They carry a lot of meaning, and the entire dispute could even be seen as a fight over the right to have the islands be called by a certain name.
So next time you refer to this particular island chain, make sure you call it by two names, unless you want your conversation to become an international incident.
