

A Chinese coast guard vessel sails alongside the Japanese coast guard ship Katori in waters off the disputed East China Sea islands on Sept. 11, 2013. (Kyodo News via AP/AP)

M. Taylor Fravel is an associate professor of political science at MIT and the author of “Strong Borders, Secure Nation: Cooperation and Conflict in China’s Territorial Disputes.” Alastair Iain Johnston is the Gov. James Albert Noe and Linda Noe Laine Professor of China in World Affairs at Harvard University and the author of “Social States: China in International Institutions.”

The dispute between Japan and China over the sovereignty of the Senkaku/Diaoyu Islands is one of the most volatile flashpoints in East Asia today. After the Japanese government purchased three of the contested rocks from a private Japanese citizen in September 2012, China began to use its coast guard to conduct regular patrols within the 12-nautical-mile territorial waters around the islands. These patrols have contributed to frictions in the Sino-Japanese relationship because they directly challenge Japan’s claim to sovereignty and administrative control. By increasing the number of ships in contested waters, China’s patrols also increase the risk of a collision or other accident that could escalate into an armed conflict between the region’s largest economies.

Daily records published by the Japanese Coast Guard on Chinese patrols suggest an intriguing change in the pattern of Chinese behavior since last fall. Although we are reluctant to infer too much about China’s bargaining strategies from these data alone, China’s history of crisis management and coercive diplomacy suggest that tactical, on-the-ground behavior offer one important means for signaling either escalation or de-escalation.

As Figure 1 shows, since October 2013 there has been a substantial decline in the frequency of Chinese patrols within the territorial waters of the Senkaku/Diaoyu Islands. Prior to that China conducted as many as four patrols per week within the islands’ territorial waters. Yet in October, more than three weeks passed in which no patrols occurred in the 12-mile zone (Oct. 2-27). Since then (our data is current as of April 4), the frequency of patrols has dropped and maintained a fairly steady average of about one patrol into the 12-mile zone every couple of weeks.

A few simple statistical tests support our observation that a shift in Chinese behavior has occurred. A Zivot-Andrews test used to identify statistical cutpoints in time series data confirms that in early October a basic change in the frequency of patrols occurred. Likewise, a comparison of the average weekly number of patrols within the territorial waters before and after October 2013 further supports this conclusion. Figure 2 shows a statistically significant decline in the frequency of patrols into the 12-mile zone after Oct. 1, 2013 (t=2.99 p=0.004, two-tailed). Note that the patrols inside the territorial waters have dropped by about half.

What might explain this shift in the frequency of Chinese patrols since October 2013? One possibility is that a number of important Asia-wide diplomatic meetings occurred during this month, including APEC, the East Asia Summit, and an ASEAN+3 meeting. Xi Jinping and Li Keqiang visited six countries in Southeast Asia. Senior U.S. officials traveled to the region affirming relations with Japan and ASEAN states. Thus, China may have reduced the number of patrols to improve China’s image during this period of intense diplomacy. There was also some optimism in October that the Chinese-Japanese relationship was manageable. But neither can account for the overall lower frequency since October, for the past six months.

Another possibility is that the pattern is just a statistical anomaly, a function of the absence of patrolling during Chinese New Years in early February, for instance. However, even if one excludes the holiday period, there is a still a statistically significant decline in the frequency of daily patrols in the 12-mile zone. Moreover, even though there were no patrols during Chinese New Year in 2014, there were some patrols during the New Year in 2013. In other words, the leadership chose not to order patrols this time round.

A third possibility is that China is using a reduction in patrols to signal a willingness not to escalate further, for the time being. Of course, China has not dropped its claims and even fewer patrols allow it to continue to challenge Japan’s sovereignty and administrative control. Nevertheless, fewer and more regularized patrols reduce the potential opportunities for incidents to occur between coast guard vessels. As a meeting of leading Chinese government analysts and scholars concluded last summer, controlling the possibility and risk of a collision at sea was “urgent.” The reduction in patrols is perhaps even more important given the further decline of political relations between China and Japan following Prime Minister Shinzo Abe’s visit to the Yasukuni Shrine in December 2013. Although political relations between the two countries are unlikely to improve in the short-term, further tensions over the disputed islands might also be avoided.

Such a signal is also consistent with the more frequent presence of Chinese coast guard vessels in the “contiguous zone” between 12 and 24 nautical miles from a state’s coastline or land feature. China’s presence here is less provocative than within the territorial waters of the islands because states do not enjoy any sovereign rights within a contiguous zone. Although the average number of daily patrols in the contiguous zone also dropped significantly after October 2013, they are still much higher than the patrols into the territorial waters. By continuing to maintain a more frequent presence in the contiguous zone, China is warning that it could easily increase patrols in the territorial waters that directly challenge Japan’s sovereignty and administrative control.

Of course, too much could be read into this shift in Chinese behavior. Nevertheless, this relatively stable pattern since last October could serve as a baseline against which to measure the effects of signaling from Japan. If cooperative signals from Japan lead to a further decline in patrolling within the 12-mile zone, or if non-cooperative signals lead to increases in the frequency of patrols, this would suggest some sensitivity on China’s part to Japanese signaling. It would be consistent with China’s apparent bargaining position that Japanese recognition of a dispute would lead to a de-escalation of Chinese activities around the islands. On the other hand, if Japanese cooperative signals are met with no changes in patrolling, this would indicate China’s bargaining position is, in fact, deceptive and that its intention to shelve the dispute is insincere. In either case, observing these data on a daily and weekly basis moving forward may provide important information about China’s bargaining intentions.