IT did not end well for Karolina Shiino, the young woman who won the title of Miss Japan two weeks ago. She has just handed her crown back after a scandal-mongering magazine revealed that she has been having an affair with a married man – Japanese beauty contests are notoriously prudish about their contestants – but there is an upside to the story.

Both Shiino’s parents were Ukrainians. After her father died her mother married a Japanese man and moved to Nagoya, where Karolina grew up from the age of five. So she is completely fluent in Japanese, she is a Japanese citizen, and she sees herself as Japanese.

Similar things happen to Chinese-born kids growing up in Vancouver and Turkish-born kids growing up in Leipzig, and nobody sees it as remarkable. Of course they are Canadian and German respectively. What else would they be? But a Ukrainian-born kid turning Japanese? Unthinkable in Japan, or at least it used to be.

As a tearful Karolina Shiino said after accepting her crown, “There have been racial barriers, and it has been challenging to be accepted as Japanese.” Diligent journalists had no trouble in digging up racist quotes to illustrate her point.

“This person who was chosen as Miss Japan is not even a mix with Japanese but 100% pure Ukrainian. Where is the Japaneseness?” said a post on X, formerly known as Twitter. But the famous Japanese obsession with being racially pure is not Japanese at all. It’s the position from which most countries that receive mass immigration started out.

In 1968, when the first wave of immigration from the West Indies was settling in Britain, a Conservative politician called Enoch Powell made a rabid racist speech warning that it would end in “rivers of blood”. His speech was condemned by ‘the establishment’, but a lot of ordinary people shared Powell’s desire to sent the immigrants home.

Half a century later, the newest actor to play Doctor Who (than whom nobody can be more archetypally British, even though he is allegedly an immortal space alien with two hearts) is Ncuti Gatwa, a man born in Rwanda and raised in Scotland. Fifteen percent of the UK’s population are immigrants, and there have been no rivers of blood.

Most people get used to diversity and many welcome it. There will always be some who cling to their prejudices, but mass immigration has peacefully transformed many countries – and Japan will be next.

Japan is still at the stage where people of the older generation, especially those of a conservative bent, still express racist views quite unselfconsciously. Former prime minister Taro Aso, for example, once described Japan as a nation of “one race, one civilization, one language and one culture.” But that was 20 years ago. He wouldn’t say it today.

Japan’s birth rate is low, its population is falling fast, and it needs immigrants if it is to keep the show on the road. Only 1.2% of the country’s population was foreign-born in 2000; that has almost doubled to 2.3% now – and the Ministry of Labour predicts that it will be 11% by 2070.

South Korea also has 2.3% foreigners in its population. It has the second-lowest birth rate in the world (Taiwan is the lowest), and although the Korean government has made no predictions of future immigration the numbers needed will probably be even higher than for Japan.

Which brings us finally to China, whose population is already falling and is predicted to halve by the end of the century. A falling population also means a population whose average age is going up, and China will need at least a hundred million immigrants in the next generation just to care for them.

Anybody who knows China today will find it hard to imagine a China where 15%-20% of the population are Indians, Filipinos, Nigerians and Indonesians, together with a sprinkling of Swedes, Americans, Japanese, etc. But if that doesn’t happen, very bad things will happen both to elderly Chinese people and to the Chinese economy.

However, the poorer Asian countries from which most of this immigration would come will only emigrate if there are not enough opportunities at home. Birth rates are already at replacement level and still falling in most of those countries and their economies are growing fast, so their citizens may not come in the necessary numbers.

In that case, the only major long-term provider of immigrants for East Asia may be Africa, where birth rates have stayed high and economic growth is not keeping up. That would be a very interesting cultural mix, but why not?

Gwynne Dyer’s latest book is The Shortest History of War