Indonesia’s Foreign Ministry has lodged a protest with Beijing over a Chinese coastguard ship that spent two days in its exclusive economic zone in the South China Sea before leaving on Monday. The incident occurred off Indonesia’s Natuna Islands. Dr Collin Koh, a Research Fellow at the Institute of Defence and Strategic Studies, said the incident was “a challenge” to Indonesia. “This latest development merely highlights the persistent problem Indonesia faces with China refusing to relent on its irredentist claims in the South China Sea based on the nine-dash line, which has already been invalidated in the 2016 award,” said Koh, referring to the verdict of an international tribunal in The Hague that ruled against China’s territorial claims. “