Far less studied are the Eurasian origin stories and enduring family legacies of those whose ethnic difference was consciously downplayed and concealed – in plain sight, over several generations – within their own Asian families.

An enduring culture of silence enabled this loss of heritage. Children, especially within traditional Chinese families, learned early that being too curious about matters that – rightly or wrongly – were considered to be no concern of theirs was swiftly condemned.

When surrounded by a general code of observed silence, younger people merely accepted without comment that Third Auntie looked darker than the rest of her generation – and had a longer, pointier nose as well – or that Second Uncle had a curiously Malay or Filipino appearance: big eyes and hairy legs, perhaps, or some other distinctive feature that differentiated him from other relatives.

Across Southeast Asia, distinctive physical appearance due to racial blending was impossible to hide; in any case, the existence of enough other people who looked much the same, and shared common ancestry and origin stories, made dissemblance and subterfuge pointless.

In consequence, culturally and ethnically singular Peranakan Chinese societies evolved across the region. And in those overseas Chinese societies down in the Nanyang (“South Seas”), where morals were laxer and the prying eyes found in home villages back in China were absent, who really cared anyway?

But in China – as ever – things were different. From Macau’s establishment as a Portuguese trading settlement in 1556-57, the western Pearl River estuary was, in effect, a constantly moving human extension of that liminal place, where diverse peoples from across maritime Asia and far beyond lived for a few seasons, or settled down for the rest of their lives.

Ethnic Chinese from Macau’s immediate hinterland also regularly came and went, and in consequence, family genealogies in the neighbouring Pearl River districts became as varied as their distinctive culinary styles.

Shun Tak (modern Shunde), with its centuries-old silk industry, offers an example of a Chinese place where generations of (largely unacknowledged) inter-ethnic mixing occurred. Other delta towns are similar.

In some outwardly ethnic Chinese families with Pearl River Delta origins, telltale traces of old-style Macanese appearance – an immediately recognisable mélange of European, Malay, Chinese and other Asian features – are readily apparent in old family photographs.

Further up the coast in Fujian, a similar situation arose around Amoy (modern Xiamen) and Foochow (modern Fuzhou) because of extensive migration to Singapore, Penang and Manila.

Many families there appear more Malay or Filipino than southern Chinese, but when questioned, nobody knows anything definite – mainly because nobody ever dared to ask.

Illegitimacy – as elsewhere – was, wherever possible, quickly and quietly swept under the carpet. Unanticipated children were quietly absorbed into extended families without much preamble, and inconvenient questions were neither asked nor entertained.

An unmarried daughter who had gone to Macau to work and who unfortunately came home “in the family way” simply had her child passed off as her mother’s late-life pregnancy – or some other equally plausible cover story.

Other than deductions made from appearance, known (or reasonably presumed) facts about an ancestor’s overseas domicile, and fragments of personal stories, curious genealogical trails thus go completely dark.