Speaking at the Shangri-La Dialogue last week, Lieutenant-General Wang Guanzhong dropped a proverbial bomb in the Island Ballroom.
Halfway through his 38-minute speech, the deputy chief of general staff of the People's Liberation Army (PLA) accused Japanese Prime Minister Shinzo Abe and United States Secretary of Defence Chuck Hagel of "coordinating" and "supporting" one another in comments targeted at China. Lt-Gen Wang said that such US-Japan collusion was "unimaginable" and went against the spirit of constructive exchanges at the dialogue.
In his keynote address last Friday, Mr Abe had criticised China - albeit indirectly - for consolidating changes "to the status quo by aggregating one fait accompli after another".
Speaking hours before Lt-Gen Wang on Saturday, Mr Hagel decried China's "destabilising, unilateral actions (in) asserting its claims in the South China Sea".
In addition to slamming China's behaviour in the South China Sea, Mr Hagel stressed that the US would remain primus inter pares in the Asia-Pacific. This was in direct opposition to China's view, which wants a regional order for Asians by Asians - a position seen to exclude the United States.
In recent months, regional tensions have involved China, be it Beijing's tussle with the Philippines and Vietnam over disputed features in the South China Sea, or its confrontation with Japan over the Senkaku/Diaoyu islands. More recently, the US has accused China of cyber espionage of industrial secrets.
Moreover, the debates at the dialogue brought into sharp relief pressing regional issues. They should help beat the path to some degree of resolution.
In his keynote speech, Mr Abe said that Japan would play a bigger security role in the region, by amending its Constitution so that Japan could come to the aid of its ally, the United States. Tokyo would also be sending coast guard ships to the Philippines to enhance the "security of the seas" (read: against Chinese intrusions).
Unsurprisingly, some Chinese delegates were shifting uncomfortably in their seats as Mr Abe spoke.
But it is probably true to say that apart from China and South Korea, many countries in the Asia-Pacific do not have major problems with Japan playing a role in regional security.
In his address, Lt-Gen Wang gave the clearest exposition of China's controversial nine-dashed line claim to the South China Sea.
China, he said, discovered the islands in the South China Sea as early as the Han Dynasty; the nine-dashed line was drawn and declared in 1948, 46 years before 1994, when the United Nations Convention on the Law of the Sea (Unclos) was ratified. Moreover, Unclos has no retrospective effect. He added an extra sting in his bite - the US has not ratified Unclos.
It is generally accepted that the nine-dashed line is not consistent with Unclos, the gold standard for assessing disputed claims to maritime areas. But China's clearer position on the nine-dashed line should add impetus to the conclusion of talks for a binding Code of Conduct for the South China Sea, which would at the least enshrine norms of behaviour.
On another front, some serious pressure was brought on Japan to admit that Tokyo has a dispute with Beijing over the Senkaku/ Diaoyu islands, and consequently should take it to third-party arbitration.
Dr John Lee, an Australian scholar, lauded Japan's "elegant" position on the islands - while Tokyo was all for the rule of law in the resolution of disputes, Tokyo maintained that the Senkaku islands were not in dispute. As a result, the rule of law did not apply.
"Congratulations," he told Mr Shinsuke Sugiyama, Japan's Deputy Minister for Foreign Affairs, with a touch of sarcasm.
The over-arching theme of the dialogue, however, was the competing narratives between China and the United States about America's role in the region.