“Whatever political stance you may have, you never insult your countrymen.”

Lam, now retired and a volunteer at New Territories Association of Societies, has never taken part in a protest before. But this time, she said she felt compelled to join in. A turnout of 10,000 is expected, according to alliance spokesman Tsang Heung-kwan.

A former member of the guerrilla squad East River Column’s Hong Kong and Kowloon Independent Brigade during the second world war when she was in her teens, Lam said: “Do you know why the Japanese used the term to call Chinese? It was to imply that they were treating us like pigs and they could kill us whenever and wherever they liked.”

The word “Chee-na” is a variation of the derogatory term “Shina” used by the Japanese during the war against Chinese people.

When the Youngspiration pair – Sixtus Baggio Leung Chung-hang and Yau Wai-ching, both of whom favour Hong Kong’s independence from China – decided to use the word when they took their oaths, they unleashed anger in their own city that now appears to have boomeranged back at them. The fallout has triggered a legal challenge of their status that could see them losing their seats.

On that chaotic morning of October 12, Yau went further and referred to the “People’s Republic of China” as the “People’s Re-f****** of Chee-na”.

Lam’s colleague in the East River column, Ho Ming-sze, 95, was as angry as Lam.

“You can have dissatisfaction with the Chinese government and the Communist Party ... How could the two guys use the term used by the Japanese during the war to insult the Chinese compatriots?” he asked.

Ho, a former head of the United Front Work Department at Xinhua’s Hong Kong branch – Beijing’s defacto embassy in Hong Kong during the colonial time, also accused Leung and Yau of being “ignorant about history”.

Ho said he was too frail to take part in Wednesday’s rally but hoped Beijing would come up with measures to clamp down on the two localists.

It is not just the likes of Lam and Ho who went through the travails of war who are upset. Thirty-something accountant Felix Chan who voted for Yau in last month’s general election said he was also disappointed in the duo. “If I do not need to go to work, I think I will go to join the rally too. We voted them into the Legco because we wanted them to protect Hong Kong’s interest. But they had acted like primary pupils.”

While the pro-Beijing camp and other community groups have demanded a public apology from the Youngspiration pair, the pan-democrats have also distanced themselves from their localist allies, saying they could not support their acts during the oath-taking.

The Youngspiration duo has remained defiant and refused to offer an apology. Leung at first said it was his Ap Lei Chau accent that caused him to pronounce “China” as “Chee-na” and later said that the term “Shina” used to be a neutral term without special connotation. He also argued he had not insulted anyone during his oath-taking because “Chee-na” was not a person.

Ironically, the oath-taking farce coincided with a similar controversy in Japan recently over two local policemen shouting “shina-jin” at protesters opposing the construction of helipads for the US army in Higashi, Okinawa prefecture.

The Osaka prefectural police department, from which the officers were sent, quickly reprimanded the two policemen for “the indiscreet and inappropriate comments”. Chief Cabinet Secretary Yoshihide Suga also criticised the officers’ behaviour as “inappropriate and extremely regrettable”. “It must not be forgiven,” he was quoted as saying by Kyodo.

Respected scholar of Hong Kong history, Professor Joseph Ting Sun-pao, rejected the two politicians’ excuses as “childish”.

Professor Ting said the term was mainly used by the Japanese after the Mukden Incident, also called Manchurian Incident, in 1931, which saw the Japanese invasion of northeastern China, then known as Manchuria.

“The reason the Japanese used it was to agitate the Chinese while trying to show superiority towards the Chinese people.”

After the second world war, the Allied Forces concluded in an investigation in 1946 that the word “Shina” carried derogatory overtones and ordered the Japanese government to ban the use of it in all official writings, he said.

Since then, the word “Shina” and its derivatives have been replaced by “Chugoku” in Japanese. Only some right-wing extremists would still use the term out of hatred for China and its people.

In one of the widely cited essays entitled “On Japanese Expressions for China”, by renowned sinologist and historian Professor Joshua Fogel of the University of California, Santa Barbara, he said that “Shina” was rarely used prior to the middle years of the Edo period, which is the period between 1600s and 1860s in the history of Japan.

When the term was employed in the early 18th century, “It carried only positive connotations”, Professor Fogel wrote. “At the time it was believed to reflect an Indian pronunciation of the toponym for China which Buddhist travellers ... had often used centuries earlier.”

Professor Chiu Yu-lok, who teaches Hong Kong history at the Open University, said the term already had special negative meaning in today’s context.

“The two young people must know the term carries negative meaning or else they would not have employed the term to refer to China when taking the oath,” said Professor Chiu, adding: “Nowadays young people use the term very casually, especially on the internet.”

In the Hong Kong context, the term is becoming more commonly used on some online forums since the rise of the so-called “anti-locusts” campaigns against Chinese tourists some two years ago. Some Hong Kong people criticised mainland tourists for snapping up goods in Hong Kong, flooding the streets, and causing a nuisance to others.

Professor Chiu also said the lack of a proper Chinese history course in the secondary curriculum was to blame.

“Young people do not fully understand the context of the term [Shina] because many of them have not studied Chinese history in secondary schools.

“Chinese history is not an independent, compulsory subject. What sort of understanding can you expect from our young people about Chinese culture and Chinese history?

“Without knowing the history of China, it is difficult for the young people to develop a sense of belonging to the motherland. The dispute itself can be a good civic education perhaps,” added Professor Chiu.

Professor Ting said the Youngspiration duo had only themselves to blame in creating the political crisis. “They have made a big mess. It has gotten too big and is out of their control now.”