Sumo Basho was a side competition held during Robot Wars: The Fourth Wars, based on the SumoTrial from the First and Second Wars. Each of the sixteen competing robots would take turns to enter a small circular stage with Shunt, with the aim of pushing the House Robot off the ring or otherwise remaining on the ring for a full 60 seconds. Competitors which succeeded in pushing Shunt off - or forcing Shunt to fall off himself - would be placed higher on the leaderboard than those which lasted the full duration. Weapons were not allowed to be used.
Panic Attack charged straight at Shunt, who easily pushed it back, Panic Attack just managing to stay in the ring. Panic Attack then pushed the House Robot a few more times, but was deflected each time. During the second attack, Panic Attack reversed and got itself stranded on the edge of the ring. Shunt rushed over to push it off, but mistimed his charge and both machines fell off the ring. The replay, however, showed Shunt had just hit the tyres first, giving Panic Attack the victory.
X-Terminator charged straight at Shunt and got its scoop underneath his own. This, in effect, beached Shunt, preventing him from moving. There was only slight movement from the two afterwards. X-Terminator seemed to be smoking at the end, most likely from the friction of its tyres, but time had run out.
Onslaught drove straight onto Shunt's scoop. However, it managed to resist being pushed off, even as it hung close to the edge. It managed to get away, then Shunt got stuck on the edge. Onslaught came in, but Shunt was able to draw away, leaving Onslaught to drive straight off.
Kater Killer's tracks should have been an advantage, but it exposed its side, easily allowing Shunt to push one track off of the platform. It was fortunate for Kater Killer that Shunt took his time in adjusting his position before finally pushing it off.
Cold Fusion Team had added two supporting spikes on the back of Pussycat to keep it upright. However, this proved to be its undoing after it drove up Shunt and fell onto its side. With Pussycat unable to get the right way up, Shunt positioned himself properly, then pushed Pussycat out of the ring.
Scorpion clashed with Shunt somewhat tentatively. Shunt was able to push Scorpion back, although not enough for it to fall off. However, Scorpion's castor slipped off, preventing it from going any further, making it easy for Shunt to finish off.
Spawn of Scutter was the first robot to take Shunt on. It hit Shunt front on with its wedge but couldn't get underneath. Shunt circled Spawn of Scutter until it got underneath Spawn of Scutter's side, and whilst he was unable to push it off the first time, he managed the second time.
Razer turned its side towards Shunt immediately, as if tempting the House Robot to push it. The two spun around each other once until Shunt managed to get under Razer's side and push it out. Razer was able to self-right and drive around the arena floor around the plinth, but the result still counted.
Shunt simply drove straight at Diotoir and pushed the Irish machine off the ring immediately. This loss was particularly ironic because Nemesis, Diotoir's predecessor, managed to defeat Shunt during the trial of Heat A in The First Wars.