SHANGHAI, CHINA—Shanghai is China’s financial capital. A former Western concession, the city today shows little sign of the many bitter political battles fought over the last century. Tourists throng the Bund along the Huangpu River while global corporations fill the skyscrapers in Pudong, across the water.

But politics in China today is a blood sport. President Xi Jinping has been taking down powerful opponents, so-called “tigers.” However, he has not revived propaganda posters, once a pervasive political weapon.

Yang Pei Ming, a tour guide, started collecting posters in 1995. He eventually set up the Shanghai Propaganda Poster Art Center. Explained Yang: “With the shift toward a more modern and forward-thinking China, it would be a mistake to forget our history.”

Now licensed by the government, the exhibit’s official name is the Shanghai Yang Pei Ming Propaganda Poster Art Museum. Yang accumulated 6000 different propaganda posters and a plethora of other tchotchke from Mao’s suffocating personality cult.

The earlier posters look more cartoonish or stylized. Soon the atrocious school of “socialist realism” took over, presenting the “reality” of the triumph of socialism—happy workers and farmers creating utopia on earth.

Whatever their form, the posters tell much about the politics of China. In one poster Mao towers over a crowd denouncing a profiteering capitalist. A 1951 poster shows a large Mao, arm outstretched, surrounded by scenes from the country, entitled “New China Under Leadership of Wise Chairman Mao.”

Not every poster had his visage. One shows members of the People’s Liberation Army being greeted by happy Chinese. Others show model families, community celebrations, happy workers building the new china, and people enjoying an abundance of food.

Some posters were more pointed politically. One entitled “Drive US Imperialism Invading Force out of China” shows a PLA soldier with a broom sweeping away the debris of a defeated foe. Many posters celebrated Beijing’s relationship with the Soviet Union.

Many posters were weapons in domestic political battles. Confronting “bandits and spies” was a common theme. Reactionaries, landlords, and other enemies also were targeted. So was the U.S.

Still, nothing beats the idyllic country scenes, of happy, well-dressed farmers planting fields of rice, leading healthy livestock, and picking fruit in bountiful orchards. Starting in 1957, however, noted Yang, “political movements started to mobilize public opinion.”

One poster shows a worker defending against a reactionary mob, declaring: “Smash the Attack from the Rightists to Defend Socialist Construction.” Many posters urged greater production and lauded “bumper harvests” in the midst of devastating famine.

The heyday of posters was the Cultural Revolution, which began in 1966. During this period Mao used posters to take the personality cult to new heights while denouncing his enemies.

Mao almost always was pictured beatifically, looking out, sometimes clapping or with arm outstretched, over the beautiful countryside or adoring masses. In one poster a man holds Mao’s little red book aloft in front of a crowd doing the same: “Proletarian revolutionary rebels unite.” The posters attacked “Russian revisionism” as well as “US imperialism.”

After Mao’s death much of the Communist Party turned against the “Gang of Four,” whose members had most enthusiastically carried out his dictates. Posters stoked the campaign: “Strike Gang of four” declares one, while another insists “Smash ‘Gang of four’.”

The pragmatic Deng Xiaoping came to power, and abolished what he called the “big character poster.” He wanted no more political crusades or ideological campaigns, no more social chaos and economic disruption.

As I wrote in Forbes online: "What’s best for China is a loss for the rest of us, at least political junkies. But Shanghai’s poster museum thankfully preserves this unique art form."

American politics has been ugly of late. But still, politics in the U.S. cannot compare with that in modern China. This tumultuous process is captured by changing Chinese poster art. The Shanghai Propaganda Poster Art Center is a “must see” for anyone visiting the city—or going online.