IT is often said that the history of the People’s Republic of China is written with the blood of martyrs.

Some were soldiers who died fighting enemies in battles; others were civilians, intellectuals or, more often than not, anonymous operatives who sacrificed themselves for the revolutionary cause.

Li Bai, a legendary telegrapher, is probably the most romanticized and iconic Communist operative immortalized on the silver screen.

A namesake of the famous Tang Dynasty poet (AD 701-762), Li is the archetype of Li Xia, the protagonist of the classic movie “The Eternal Wave” (1958).

Few of my peers might have seen this film, let alone Millennials who only have vague ideas of movies shot well over half a century ago.

But the film indeed contains memorable scenes with which many are familiar. For example, Li, played to perfection by late Chinese actor Sun Daolin, calmly finishes sending a telegram despite being held at gunpoint by Kuomintang spies who barge into his hideout.

I was curious if Li was as heroic as portrayed in the film. And that’s the reason I paid a visit recently to his former residence on Huangdu Road in Hongkou District.

Tucked away on a side street, this three-story brick house was where Li last lived and fought. It is now arranged in the style of a memorial.

On stepping into the memorial, one sees a sculpture of Li. Bespectacled and round-faced, he radiated the air of a countryside teacher. He could have become a teacher, but destiny put him on a trajectory toward a dramatic life.

Born in 1910, in the dying days of the Qing Dynasty (1644-1911), Li chased dreams of national salvation like youngsters of his age.

He joined the Chinese Communist Party at 15, participated in an armed uprising against the KMT and joined the Long March. He studied to become an expert at radio transmission.

After Shanghai fell in the battle between the KMT and Japanese troops in 1937, the city became a “lone island” cut off from the outside world.

To acquire information for revolutionary leaders in Yan’an, the Communist stronghold, the Party sent Li to work in Shanghai, then a snake pit, to help reconnect Shanghai’s underground Party units with their superiors.

It was a perilous time to be in Shanghai as a spy, and Li encountered danger all the time. Japanese military vehicles patrolled the streets all day to check for suspicious radio waves.

To avoid being discovered, Li chose to send intelligence in the dead of the night, when Japanese policing was the lightest.

To avoid being seen and mute the tapping noise, he threw a dark cloth over the light bulb and pressed the radio button more gently.

Under the Party’s arrangement, a cotton mill worker and Communist Party member Qiu Huiying “married” Li to provide cover for his activity. Inspired by the same ideals, they later became a true couple.

To acquire more knowledge about radio techniques, Li sought a job with a local radio company as a bookkeeper, where he learned to repair radios. It turned out to be a significant decision.

In September 1942, Li and his wife were arrested in a Japanese raid. The horrors of torture didn’t break him — he insisted that the radio found at his home was used for private purposes.

As his son Li Hengsheng once recounted, the Japanese finally released his father, mainly because they lacked the smoking gun to prove he was a spy.

Li’s radio transmitter looked no different than ordinary radios, except for one thing: Once equipped with a small metal coil that worked as an antenna, the radio could be used for sending and receiving telegrams.

So before the Japanese spies broke in, Li had time to remove and dispose of the coil, depriving the enemy of the evidence to incriminate him.

In 1944, tides turned in the War of Resistance Against Japanese Aggression (1931-1945).

China began to regain lost land. Intelligence at this point proved more important than ever. At the Party’s behest, Li, under the pseudonym Li Jingan, traveled with his wife between Zhejiang and Jiangxi provinces, taking advantage of his public identity as a KMT official to pass on information to superiors.

The eternal wave goes on

Soon a fateful ferry ride resulted in his radio being discovered by KMT police. And he was arrested for the second time. Nonetheless, KMT and Communists were still collaborators in their quest to expel the Japanese invaders. After rescue efforts were made, Li was delivered from KMT incarceration.

In September 1945, one month after Japan surrendered, Li wrote his father in apparent exultation that “victory is ours! After so many years fighting for the country and people, the day has finally arrived. We should enhance domestic solidarity and build a new China.”

His hopes were dashed. China was soon plunged back into a civil war. In October 1945, Li returned to Shanghai with a new mission. He worked as a researcher with a KMT institute during daytime and sent intelligence at night. To avoid being detected, he managed to contact superiors through extremely weak radio waves.

In 1948, bruised by a succession of military defeats, the KMT became increasingly desperate. It resorted to sporadic power cuts to try to seek out Communist radio stations and destroy them.

In the wee hours of December 30, 1948, Li was arrested when sending a confidential piece of information about the KMT’s defensive works along the Yangtze River.

He was tortured and interrogated for over 30 hours on end. His fingernails were pulled out, bamboo sticks were driven into his fingers, and he was forced to sit in a so-called lao hu deng, a torture chair in which the victim had his legs strapped to a bench and bricks piled up under his feet, until kneecaps were disjointed — or confessions were extorted. But no matter how the enemies tortured him, Li refused to talk.

The KMT held him until May 7, the last day Li met his wife and son, who was only a little over a year old.

Following her husband’s instructions, Qiu stood on the balcony of a home opposite the prison. Through a tiny cell window, she saw Li, emaciated and disheveled. Li told her not to come again, as “she and other countrymen would soon be free.”

As for the son, he promised to “go home and hug him in a few days.”

The paternal warmth never came. On that very night, which happened to be Li’s 39th birthday, the hero was executed together with 11 other comrades near a temple in Pudong — only 20 days before Shanghai’s liberation.

The remains of these Communists were exhumed in June and then interred in a cemetery. They were recognized as revolutionary martyrs.

On the third floor of Li’s memorial are small living quarters, with different objects on display: radio transmitters encased in glass boxes, posters of the 1958 film hanging on the wall. And visitors are encouraged to tap a button on the desk to imagine what it was like for Li to work under grave pressure.

One of the memorial’s descriptions says: “Li Bai sent the eternal wave with his life and zeal; he sounded the last note of his life to the Party and people.”

The eternal wave goes on.