With apologies to John Lennon, imagine that the Chinese fishing trawler captain now in detention in Japan was not a lone individual, but one of several hundred fishermen captured and held over the past 18 months or so. Imagine, too, that some of their boats had been rammed and sunk by Japanese patrols; others, meanwhile, had their catches seized.
Or that once in detention, at times for months, Japan had offered their release only after the payment of thousands of dollars per head. Their government objected to the payment of ransoms, but some families were so desperate to see their fathers, sons and husbands that they quietly paid up. Rumours spread that some had been shot.
I put such a scenario to a mainland student friend. He was shocked. 'I cannot even imagine the outcome,' he said. 'There would be such anger against the Japanese government that I cannot believe that ordinary Japanese would be safe in China.' Certainly it does not bear thinking about, given the feverish pitch to the diplomatic and social pressure now building on Tokyo over the continued detention of the captain.
Yet this scenario has happened, but not involving Japanese patrols against Chinese fishing boats over the disputed islets of the East China Sea. Instead, it represents the actions taken by Chinese vessels in the disputed South China Sea against Vietnamese fishermen. Instead of the Diaoyu Islands, most of the detentions have taken place in waters surrounding the Paracel archipelago - claimed by both countries but occupied by China since 1974.
Vietnam's Foreign Ministry has lodged formal protests while its state press, a less sophisticated but equally unsubtle variant of the mainland model, has churned out tales of woe from grieving relatives waiting for news. Under pressure from annoyed Chinese diplomats, Vietnamese government officials have tried to keep nationalistic tensions from spilling over into street protests.
This situation is worth reflecting on, whatever the rights or wrongs of the Diaoyu issue or the excesses of Vietnamese fishermen - who have also been detained in Indonesia and Malaysia in recent years. For many officials in the region, China's actions highlight a 'do as I say, not as I do' coercion that appears to presage an era of dominance by Beijing. The Vietnamese detentions have certainly resonated in diplomatic salons across a wary region and provided an opportunity pounced upon by the US.
As this column has noted before, no one in the region seems to want to contain China, but they certainly don't want to be bullied and/or find themselves ultimately beholden to a single superpower. Balance, therefore, is the name of the game. This mood has resonated in Washington, with US military brass unusually expressing alarm at the plight of the Vietnamese fishermen, just as US officials sought to re-engage with an East Asia that felt neglected.
The result? The United States has been formally invited to play a role in the East Asian summitry of the Association of Southeast Asian Nations. At the same time, it has buttressed the clout of Asean in solving South China Sea disputes with China by saying that finding a peaceful, multilateral solution was a US diplomatic priority - a move that has angered Beijing.
These issues are set to surface in Hanoi next month when Vietnam chairs a historic first meeting of the 10 defence ministers of Asean and counterparts from China, Japan and South Korea as well as the US and Russia.
All of these landmark shifts on the regional diplomatic and strategic stage have come under Vietnam's watch as chairman of Asean. That baton will soon pass to Indonesia, an increasingly assertive nation that has had its own problems with China in the South China Sea, given the reach of Beijing's historic claim.
The intensifying diplomatic posturing surrounding the detention of the Chinese trawler captain in Japan is stirring deep nationalistic sentiments across greater China, and it risks stirring other fears across a region attempting to stand up to Beijing.
Greg Torode is the Post's chief Asia correspondent