Sarcastic laughter and ironic applause echoed through the Crucible Theatre in Sheffield on the evening of 1/5, as two top players, Wu Yize and Mark Allen, repeatedly played safety shots instead of attacking. Referee Marcel Eckardt frequently had to appeal for quiet, but the audience's impatience grew with the prolonged stalemate.

The unusual situation unfolded in frame 14 of the quarter-final match, with Northern Irish player Allen holding a 7-6 lead in frames. Allen was also ahead 43-13 in the current frame, poised to extend his advantage. However, the game ground to a halt when a cluster of eight red balls became virtually unpottable, blocked by the black ball in a corner pocket.

The ball deadlock in the match between Wu Yize and Mark Allen at the World Snooker Championship in the Crucible Theatre, Sheffield, United Kingdom, on the evening of 1/5. Photo: PA

In snooker, players often opt for safety shots when scoring opportunities are absent, strategically placing the cue ball to force an opponent's error. Yet, at the Crucible, this tactical approach became an interminable cycle. Both players took turns making minimal contact, sending the cue ball to the cushion or concealing it behind other colored balls, with the table layout remaining almost unchanged for an extended period.

What began as an intense tactical battle for the audience soon devolved into widespread mockery. Each safety shot was met with sarcastic cheers, prompting Referee Eckardt to audibly request, "We don't want that, please calm down." BBC commentator and seven-time world champion Stephen Hendry labeled the incident the "dark side of snooker," questioning the potability of any red balls even if the black ball were freed.

The core of the problem lay in the rules of play. In a prolonged stalemate, the referee possesses the authority to restart the frame, re-racking the balls to their initial positions. This decision, however, is often contentious, as it can negate any advantage a player has painstakingly built up.

Allen visibly reacted with anger when Eckardt announced a potential restart if the situation did not change after three more shots. As the leading player, he was reluctant to forfeit his advantage after nearly one hour of play in the frame. To avoid a replayed frame, Allen deliberately broke the deadlock by hitting the black ball, accepting the inherent risk.

The situation where red balls could not be potted. Photo: screenshot

This risky decision by Allen proved to be a turning point for Wu. From a 13-43 deficit, the Chinese player gradually gained control as the red balls became accessible. Freed from the intense pressure, Wu played more comfortably, steadily closing the gap. He eventually took a 61-47 lead with only two red balls remaining. Hendry suggested that the chaotic nature of the frame had psychologically freed Wu, who had earlier shown signs of flagging and appeared unlikely to win another frame.

The frame, however, was not yet over. Allen still had an opportunity to snooker and reverse the outcome but missed a crucial shot. Shortly after, Wu potted the pink ball, concluding the frame in 100 minutes and 21 seconds – the longest in World Championship history, surpassing the previous record of one hour and 25 minutes. Not long after the frame's conclusion, six-time world champion Steve Davis also voiced his criticism on BBC, stating, "In short, this frame was a disgrace to snooker. The referee and the players' association need to find a way to prevent this from happening again."