Question: When did the torch arrive in the birthplace of Ri Hyon-ju?

full_context: Document 1: Kim Jong-un: Scarce information on Kim Jong - un's early life comes from North Korean defectors and people who have claimed to witness him abroad, such as during his school attendance in Switzerland. Some of the information has been conflicting and contradictory, perhaps confusing him with his brother, Kim Jong - chul, who also attended school in Switzerland around the same time. Nevertheless, there has been some consensus on information about his early life. North Korean authorities have stated that his birthdate is 8 January 1982, but South Korean intelligence officials believe the actual date is a year later. Former basketball star Dennis Rodman said that the birthdate is 8 January 1983 after meeting Kim in September 2013 in North Korea. Kim Jong - Un was the second of three children Ko Yong - hui bore to Kim Jong - il; his elder brother Kim Jong - chul was born in 1981, while his younger sister, Kim Yo - jong, is believed to have been born in 1987.
Document 2: Ryang Yong-gi: Ryang Yong-gi (; born 7 January 1982 in Tadaoka, Osaka) is a Japanese-born North Korean footballer who plays for Vegalta Sendai in the J. League Division 1.
Document 3: 2008 Summer Olympics torch relay: In many cities along the North American and European route, the torch relay was protested by advocates of Tibetan independence, animal rights, and legal online gambling, and people protesting against China's human rights record, resulting in confrontations at a few of the relay locations. These protests, which ranged from hundreds of people in San Francisco, to effectively none in Pyongyang, forced the path of the torch relay to be changed or shortened on a number of occasions. The torch was extinguished by Chinese security officials several times during the Paris leg for security reasons, and once in protest in Paris.
Document 4: North Korea at the 2008 Summer Olympics: North Korea (Democratic People's Republic of Korea) competed in the 2008 Summer Olympics, held in Beijing, People's Republic of China from August 8 to August 24, 2008. The country sent 63 athletes, competing in 11 sports.
Document 5: Rim Ju-song: At the time when he was selected, he was living in Beijing. By the time North Korea received clearance to compete in London, it was "too late to qualify for most events, but swimming was an exception". Thus North Korea's representative would have to be a swimmer. Rim, who did not know how to swim, began to learn the crawl stroke in April 2012, reportedly with great difficulty at first, and the breaststroke in May.
Document 6: 2008 Summer Olympics torch relay: After being lit at the birthplace of the Olympic Games in Olympia, Greece on March 24, the torch traveled to the Panathinaiko Stadium in Athens, and then to Beijing, arriving on March 31. From Beijing, the torch was following a route passing through six continents. The torch has visited cities along the Silk Road, symbolizing ancient links between China and the rest of the world. The relay also included an ascent with the flame to the top of Mount Everest on the border of Nepal and Tibet, China from the Chinese side, which was closed specially for the event.
Document 7: Quah Zheng Wen: In June 2012, he set a national record in the 200 m individual medley. At the 2012 Summer Olympics he finished 33rd overall in the heats in the Men's 400 metre individual medley and failed to reach the final.
Document 8: Ri Hyon-ju: Ri Hyon-ju (born 20 February 1996 in Pyongyang) is a North Korean diver. He competed in the 10 metre platform at the 2012 Summer Olympics.
Document 9: Ryang Chun-hwa: Ryang Chun-hwa (; ; born 12 June 1991 in Pyongyang) is a North Korean weighlifter. She competed at the 2012 Summer Olympics in the Women's 48 kg, winning the Bronze medal. Ryang represents the April 25 Sports Team. She won the silver medal at the 2011 Summer Universiade.
Document 10: 2008 Summer Olympics torch relay: Thailand: The April 18 relay through Bangkok was the Olympic flame's first visit to Thailand. The relay covered just over 10 km, and included Bangkok's Chinatown. The torch was carried past Democracy Monument, Chitralada Palace and a number of other city landmarks. M.R. Narisa Chakrabongse, Green World Foundation (GWF) chairwoman, withdrew from the torch-running ceremony, protesting against China's actions in Tibet. Several hundred protesters were present, along with Olympic supporters. Thai authorities threatened to arrest foreign protesters and ban them from future entry into Thailand. A coalition of Thai human rights groups announced that it would organise a "small demonstration" during the relay, and several hundred people did indeed take part in protests, facing Beijing supporters. Intended torchbearer Mom Rajawongse Narissara Chakrabongse boycotted the relay, to protest against China's actions in Tibet. In Bangkok, students told the media that the Chinese Embassy provided them with transportation and gave them shirts to wear.
Document 11: 2008 Summer Olympics torch relay: North Korea: The event was held in Pyongyang on April 28. It was the first time that the Olympic torch has traveled to North Korea. A crowd of thousands waving pink paper flowers and small flags with the Beijing Olympics logo were organized by the authoritarian regime watched the beginning of the relay in Pyongyang, some waving Chinese flags. The event was presided over by the head of the country's parliament, Kim Yong Nam. The North, an ally of China, has been critical of disruptions to the torch relay elsewhere and has supported Beijing in its actions against protests in Tibet. Kim passed the torch to the first runner Pak Du Ik, who played on North Korea's 1966 World Cup soccer team, as he began the 19-kilometre route through Pyongyang. The relay began from the large sculpted flame of the obelisk of the Juche Tower, which commemorates the national ideology of Juche, or "self-reliance", created by the country's late founding President Kim Il Sung, father of leader Kim Jong Il, who did not attend.
Document 12: 2008 Summer Olympics torch relay: Kazakhstan: The first torchbearer in Almaty, where the Olympic torch arrived for the first time ever on April 2, was the President of Kazakhstan Nursultan Nazarbaev. The route ran 20 km from Medeo stadium to Astana Square. There were reports that Uighur activists were arrested and some were deported back to China.
Document 13: 2018 Winter Olympics torch relay: The 2018 Winter Olympics torch relay began 24 October 2017 and ended on 9 February 2018, in advance of the 2018 Winter Olympics. After being lit in Olympia, Greece, the torch traveled to Athens on 31 October. The torch began its Korean journey on 1 November, visiting all Regions of Korea. The Korean leg began in Incheon: the torch travelled across the country for 101 days. 7,500 relay runners participated in the torch relay over a distance of 2,017 km. The torchbearers each carried the flame for 200 metres. The relay ended in Pyeongchang's Olympic Stadium, the main venue of the 2018 Olympics. The final torch was lit by figure skater Yuna Kim.
Document 14: Ri Sang-sim: Ri Sang-sim (; born October 10, 1979 in Pyongyang) is a North Korean judoka who competed in the women's half-lightweight category. She finished fifth in the 52-kg division at the 2003 World Judo Championships in Osaka, Japan, and also represented her nation North Korea at the 2004 Summer Olympics.
Document 15: Ri Se-gwang: Ri was the first North Korean ever to win a gold medal on vault at the Asian Games, where he performed solidly at the 2006 Asian Games and was the first one for North Korea on that apparatus. He later went on to win a bronze medal on vault at the 2007 World Artistic Gymnastics Championships.
ground_truth: April 28
sub_queries: Ri Hyon-ju >> place of birth Answer: Pyongyang
When did the torch arrive in Pyongyang ? Answer: April 28