Maybe this has something to do with culture of Japanese men. After reading much history and comments. It's history of union with black women were either by empire conquest or male dominated migration (too much baby killing and abandoning wife, children).Happened in Africa, Pacific islands, only Carribeans they didn't killed babies, or abandoned wife, children. Chinese men are different, when around 300,000 to 500,000 Chinese male coolies migrated to Latin America and Carribeans, they intermarried with Black women without killing babies or abandoning children.

Japanese cruelty could be explained by relations with Mongol men and Turkic men. The population of 50 millions Central Asians, 600,000 Nogais in Caucasus, 11 million Hazaras in Afghanistan, Iran, Pakistan are all created from Mongolian men intermixing with Iranian white women, caucasian/Middle eastern women, Pakistani women by invasions/conquest by Mongol empire. Also by Turkic Asian men during Turkic empires (Relation with Japanese is evident in their sumo/wrestling, arrow bow culture, Altaic language family)

In Angola

(Due to male only migration)

Also known as "Katanga infancide". More than 1,000 Japanese male miners over 10 years period intermixing from 1970's, hundreds to thousands babies Afro-Japanese born but only 50 survied. This was due to everyday Japanese men prostituing women from poverty class, tribal women, or seeking sex with local black women who wanted marriages, only handful cases of marriages, every ( ALL END UP killing their babies or abandoning their wifes, children).


In New Guinea, East Timor, Micronesia

The people of those territories are related with Australian aborigines in looks and skulls. The population of all those Australian aborigine-related like people occupied by Japanese were less than 2 million, around 1.5 million. Before even in 1900's they were only few hundred thousands and their population only started growing after the 1950's

Happened during Japanese migration since 1901, later occupied New Guinea and others like Solomon islands, New Britain from 1941 to 1945

https://en.wikipedia.org/wiki/Japanese_settlement_in_Papua_New_Guinea

https://en.wikipedia.org/wiki/Japanese_occupation_of_New_Guinea

* A Papuan activist from Western New Guinea claimed an estimated 16,161 Papuan New Guinean comfort women were used by Japanese male soldiers during their occupation of New Guinea.[91]


* During World War II the Imperial Japanese Army invaded New Guinea with 350,000 troops and occupied most of its territory from January 1942 to August 1945. Some Papuan women including mixed-race Japanese-Papuan women were forced to become comfort women. one Australian Captain, David Hutchinson-Smith, also mentioned of some mixed-race, young Japanese-Papuan girls who were also conscripted as comfort women.[6]


And before that as male dominated migrations ( 100 Japanese males coming in and out from 1901 to 1945, constantly changing after a year )

* As almost all the migrants were men, many of them married local Papuan wives and raised mixed-race Japanese-Papuan families while other Japanese men staying only for short periods also had sexual cohabitations with local Papuan women, but in most cases without marrying. Many of them did produce offspring but they were generally abandoned by their Japanese fathers (some of whom were already married with children in Japan) and raised by their single Papuan mothers or sent to the orphanage. These abandoned mixed-race children's were recorded as ethnic Papuans in the census as the ethnicity of their fathers was unknown.

As you can see New Guinean women look black too but related to Australian Aborigines.


In East Timor

Sexual Violence Against East Timorese Women During the Japanese Occupation

60,000-70,000 East Timor died from Japanese occupation

https://etan.org/issues/ww2.htm

* Under Japanese occupation, the borders of the Dutch and Portuguese were ignored with Timor island being made a single Imperial Japanese Army (IJA) administration zone

* Besides Dutch women, many Javanese were also recruited from Indonesia as comfort women, including around 1000 East Timorese women and girls who also used as sexual slaves.[89]

* There were thousand descendants of Japanese soldiers from 1940's


Micronesia (1914 - 1945 )

*"n 2001, the director of Japan's Institute for Pacific Studies Izumi Kobayashi estimated that at least 23% of FSM's ( Micronesians ) population was of Japanese ancestry.[22] An official estimate in 2006 puts the number a little below 20%.[59]

* A sizable minority also have some Japanese ancestry, which is a result of intermarriages between Japanese settlers and Micronesians during the Japanese colonial period.[39]

* Estimates 1 in 4 are descendants of Japanese colonial settlers who intermarried with local Micronesian females, some also have ancestry from intermarriage with Filpino male settlers.

Cuba

The only acception is Cuba, a small group 560 Japanese men married Cuban women without doing what they did in Africa.

About 120,000 Cantonese laborers, all males, entered Cuba under contract for 80 years; most did not marry, but Hung Hui (1975:80) cites there was a frequency of sexual activity between black women and Cantonese coolies. According to Osberg (1965:69) the free Chinese conducted the practice of buying slave women and freeing them expressly for marriage. In the 19th and 20th centuries, Chinese men (Cantonese) engaged in sexual activity with both White and Black Cuban women and from such relations many children were born.[Americas-Cuba 1]

In the 1920s an additional 30,000 Cantonese and small groups of Japanese also arrived; both immigrations were exclusively male and there was rapid intermarriage with white, black and mulato populations.[Americas-Cuba 2] The CIA World Factbook Cuba, in 2008, claimed a population of 114,240 Chinese-Cubans, with only 300 being just Chinese.[Americas-Cuba 3]

One of Cuba's most known Afro-Asians is the artist Wifredo Lam.

Japan/China and Russia are originally black