The heir to China`s throne lives in an old house with a courtyard in which the last chrysanthemums of fall sprout amid a heap of coal briquettes collected for the winter. Three cats, Little Black, Big White and Small Flower, keep him company.

Prince Aisin Giorro Pu Jie is the younger brother of the ruler depicted in the movie ''The Last Emperor,'' Henry Pu Yi, who died in 1967. He has courtly manners, but wears the haunted expression of a man groomed to be a puppet emperor by the Japanese, vilified as a decrepit aristocrat by the Soviets and labeled a traitor by the Chinese Communists.

On Saturday, the frail 86-year-old prince donned his black tailcoat, straightened his thin shoulders and went to see Emperor Akihito at the Japanese Embassy. It was a glittering reception in honor of the first imperial visit to China in 2,000 years.

''We will bow to each, and I will simply say: `Welcome to China,` '' the prince chuckled during an interview last week. As heir to the throne, Pu Jie is aware that he may address Akihito as an equal.

But their lives are vastly different. The prince lives in a former carpet factory at 52 Huguosi St. and outside his walled courtyard, butchers sell meat so fresh it still drips blood, women yell the price of cabbages, cucumbers and lemongrass, music pounds from a dance hall and shoppers stream in and out of a new department store.

The house is just a stone`s throw from the Forbidden City, the imperial palaces now turned into museums, where his Manchu ancestors ruled China under a ''mandate of heaven.'' There the prince was brought up among 1,000 eunuchs and 100 concubines.

In 1911, when Pu Jie was 5, Sun Yat-sen proclaimed China a republic. Pu Yi, Pu Jie and their nine brothers and sisters continued to live in their separate palaces, but without power over the life and death of their compatriots. It would be another five years before the brothers would meet for the first time.

The fall of their dynasty rankled them. When Japan invaded Manchuria in 1931 and created the puppet state of Manchukuo, Pu Yi agreed to become its emperor. Meanwhile Pu Jie went to Japan, where he spent several years tucked away at military academies.

He married Princess Hiro Saga, a cousin of the late Emperor Hirohito, and became an important pawn in the grand Japanese strategy of an Asian empire under Tokyo`s tutelage. He was sent to Manchukuo in 1939 to head his brother`s imperial guard, a post he held until the colony collapsed with the arrival of Soviet troops in 1945.

''We thought we could use the Japanese to regain power, but instead they used us,'' he recalled as he snuggled into his favorite armchair. ''I have apologized to China for being a traitor, but neither my brother nor I realized that until many years later.

''All we wanted was the throne back. We would have made a deal with any foreign country willing to help.''

Ironically, Pu Jie does not believe Beijing should demand an apology from Akihito for the millions massacred during Japan`s occupation of China during World War II.

''When it`s peaceful, why bring up unpleasantries?'' Pu Jie asked.

''Japan and China are like a couple; they always quarrel, but in the end they make up. The apology is a minor issue.''

His answers are cautious. He has learned to be careful after being duped by the Japanese to believe in Tokyo`s invincibility, spending five years in a Soviet gulag and another 10 years in a Chinese Communist re-education camp where he was taught that he is no more than a speck among the great mass of China`s people.

He repeats his self-criticism almost cynically. ''In the past I was a drop of foul water. Now I`m immersed in the sea of 1 billion people,'' he said.

He deeply felt the death of Prime Minister Chou En-lai in 1976. It was Chou who in 1960 transformed the carpet factory into a comfortable home for Pu Jei and provided a maid, a monthly salary of $110 and an official job as

''scholar of Manchu.'' More importantly, Chou`s influence kept away the radical Red Guards.

Only when he talks about his childhood does a smile light the prince`s ascetic features and a mischievous twinkle enter eyes that have seen so much during this turbulent century in Asia.

''I was 10 years old before I first met my brother, who was emperor since he was 3,'' he recalled. ''I always thought the emperor was an old man with a beard. I was so shocked. He was only a little boy like me.''

It would be another 34 years before Pu Jie could address his brother as

''Elder Brother'' instead of your ''Your Imperial Highness.'' By then it was 1950. The brothers, who had been captured by Soviet troops as they attempted to flee Manchukuo, had spent five years together in a Siberian gulag. Now they were to be handed over to Mao Tse-tung`s Communists who would send them to a re-education camp.

He remembers the Soviet guards as cruel and nasty. ''They told us we would be excecuted once they handed us over to the Chinese,'' he recalled.

''Pu Yi and I were really scared. We thought we would die for sure.''

But even Mao`s followers apparently were afraid to harm the sons of heaven. ''They treated us kindly and in the camp they even let us play mahjong though gambling was prohibited,'' he said. ''The guards said we couldn`t use real money, but we could use cigarettes. It wasn`t so bad.''

The brothers were released in 1960, rehabilitated as private citizens. It took Pu Jie and Chou another year to convince the former emperor that Hiro Saga, who had remained in Japan, should come to China.

''My poor brother was convinced her coming to China was another Japanese plot to harm us,'' he recalled.

Pu Jie`s wife, who had kept rabbits, chicken and even monkeys in the garden, died five years ago. Half of her ashes are buried in the Revolutionary Cemetery in Beijing, the rest in the Imperial Cemetery in Japan.

His oldest daughter committed suicide in Japan over a love affair. The second daughter, married to a Japanese factory owner in Kobe, and his five grandchildren live in Japan.

His brother spent his final years as a handyman in Beijing`s Botanical Gardens and died of liver cancer. His brother`s wife, Empress Wan Rong, died during forced withdrawal from opium addiction.

The sun comes in through the window and plays on the family portraits and the rolls of calligraphies on the wall. ''Oh yes,'' the old prince said,

''sometimes I take old friends for a walk through the Forbidden City and then my childhood comes back to me.''

Did he ever sit on the emperor`s throne. ''No, no,'' he said indignantly. ''That was Pu Yi`s chair.''