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On the April 7 installment of the JTBC variety show, all the Wanna One members appeared as guests to promote their latest track "Boomerang", which has been winning them music show trophies. Wanna One started to compete to show each of their talents, and Bae Jin Young suddenly expressed his skill with the ancient board game baduk (Go). 

Lee Soo Geun quickly suggested, "Instead of that, you should just show us your stomach." Park Woo Jin then shocked everyone by showing how much air he could put into his stomach, making it look like a bowling ball, followed by Park Ji Hoon showing his stomach. 

Kang Daniel also tried, but his abs surprised everyone enough. The 'Knowing Brothers' cast commented, "It's like a washboard."