WASHINGTON - With the excitement and controversy swirling around Lei Yixin and his 9-meter-tall granite statue of Martin Luther King Jr at the National Mall, the so-called Chinese master sculptor is surprisingly calm and modest.

For the past four years, Lei has battled rejection from detractors who have openly said Lei is the wrong sculptor for the job. After the statue's unofficial unveiling this past Monday, both praise and criticism have been lobbed at Lei.

"My nerves have been on the verge of collapse over the past four years," said Lei from his son's home near Washington DC.

The official unveiling, slated for Sunday, of the Martin Luther King Jr. National Memorial will be delayed because of the weather. The Sunday date marks the 48th anniversary of the "I Have a Dream" speech that Dr King delivered from the steps of the nearby Lincoln Memorial in 1963. The speech includes the phrase: "Out of a mountain of despair, a stone of hope".

Visitors will walk through two massive granite halves of the "Mountain of Despair" to reach the "Stone of Hope," from which the sculpture of King emerges.

Behind the sculpture is a 137-meter-long wall inscribed with 14 quotes from MLK's speeches, sermons and writings.

The 57-year-old sculptor who has created more than 100 public monuments in China including giant sculptures of Chairman Mao Zedong recently recalled the enormous pressure he faced in an interview with China Daily.

Dressed in a white shirt and light khaki pants, the tall Chinese artist, with his signature shoulder-length hair, moustache and round glasses, said he was afraid that during the making of the sculpture, the threat of being fired hung over his head every day.

He said it was hard for many Americans to understand why a Chinese sculptor was chosen for the monument. Critics have said that Lei shouldn't have been selected for the statue of MLK because he made the statues of Mao Zedong.

Born in Central China's Hunan province to an educated family, Lei was one of many bourgeois youths sent to the countryside for re-education during the "cultural revolution" (1966-1976). He said he tilled the land in a mountainous region of Hunan for eight years.

He developed his passion for drawing during those formative years and was accepted to an art school in 1978. Since then, Lei has become a well-established artist in China, with several of his works on display in China's National Art Gallery.

Ed Jackson, the chief architect of the MLK Memorial, was impressed with sculptures done by the Chinese artist. He and the MLK Memorial Foundation had spent six years hunting globally for a sculptor for the monument.

During those six years, the scouting team from the foundation decided to try their luck at Minnesota Rocks! Symposium in June 2006. They were immediately impressed by Lei's sculpture "Contemplation".

"I was taking a nap under a tree when my wife woke me up to introduce some people from the MLK Memorial Foundation," Lei recalled. "I could not believe then that they invited me to create a sculpture of such a great person."

The long search has been rewarding for Jackson and Lei. Jackson said that when he first saw the completed statue, "it took my breath away".

"When (Lei) sent me an email of his clay version of the head that was three feet high, the first words that came to my mind were, 'He nailed it! He got it,'" Jackson said.

The 159 granite blocks used to make the 9-meter-high statue of MLK weighed some 1,600 tons and were picked and carved in Quanzhou, Fujian province, and shipped from Xiamen to the port of Baltimore. A team of 10 Chinese stone-masons were brought over to help assemble the statue.

Lei said he is a great admirer of MLK. He said his favorite quote from the legendary activist is: "Darkness cannot drive out darkness; only light can do that. Hate cannot drive out hate; only love can do that".

Though many US celebrities have lined up to get his autograph, he was most touched by two African American women he met at the memorial site.

"When they knew from the security guard that I am the sculptor, they approached me and shook my hand, saying 'We just want to thank you for your great work.'"

When he returns to China, Lei said he will focus on setting up a sculpting school in his name in his hometown.

Due to difficulties in communication and work styles, "I will be very cautious taking any offer from other countries in the future," he said.