The term 'Clash of Heavyweights' can be summarized as a battle between two powerful opponents. In this case, the two opponents are SUMO wrestlers, which is a Japanese form of wrestling where two large, heavy-set wrestlers compete against each other in a ring. The goal is to force the opponent out of the ring or to make them touch the ground with any part of their body other than the soles of their feet. SUMO is considered a national sport in Japan and is often used as a metaphor for a clash between two powerful forces.