evidence: Yet another incident involving a Chinese coastguard vessel and an Indonesian patrol boat has occurred in the vicinity of Indonesia’s Natuna Islands in the South China Sea. Unlike the previous incidents, this time the Chinese coastguard vessel almost intruded into Indonesia’s 12-nautical mile territorial sea off Bunguran (Natuna Besar) Island (see the map below). [...] While seemingly escalatory at the tactical level, this incident did not signal a new Chinese modus operandi at the strategic level. China is renowned for using its fishermen as proxies to enforce its nine-dash or U-shaped line claim in the South China Sea, a claim that partly overlaps with Indonesia’s 200 nautical mile exclusive economic zone near the Natuna Islands. But the way Indonesia responded to the latest incident was different: the KKP reversed Indonesia’s official tendency to downplay maritime incidents involving Chinese government vessels near the Natuna Islands. [...] While the Indonesian government has made promises to boost naval defenses and maritime law enforcement in the Natuna Islands, implementing those plans has become even more urgent now. Unfortunately, time is not on Indonesia’s side. The fortification and militarization of Chinese-occupied features in the Spratly Islands is continuing apace, which will eventually enable Beijing to impose greater sea control over the U-shaped line, including in the waters near the Natuna Islands. These features could also become springboards for Chinese long-distance fishermen to venture further south, escorted by the Chinese Coast Guard.