Before revision: In December 2015, Lance Tschirhart entered the Guinness Book of World Records for memorizing a sequence of 456 digits spoken aloud at the rate of one per second at the World Memory Championship in Chengdu , China.
After revision: In December 2019, Ryu Song I entered the Guinness Book of World Records for memorizing a sequence of 547 digits spoken aloud at the rate of one per second at the World Memory Championship in Wuhan , China.