With the 2023 ODI World Cup having reached the knockout stages, reserve days come into play for the semi-finals on November 15 and 16 and then the final on November 19. While there is virtually no chance of them being needed when India face New Zealand in Mumbai, there is the prospect of rain impacting the Australia-South Africa clash in Kolkata so here's a rundown of how things work.

Is the forecast that worrying for Kolkata?

Well, as ever, it depends which website you look at, but there is certainly a reasonable threat of rain playing a part. At the moment, Friday looks the more problematic day, with Thursday, the scheduled day of the semi-final, having a prediction of around a 50% chance of seeing showers.

When does the reserve day come into play?

If a match isn't completed on the scheduled day, and the reserve day is used, there are basically two scenarios for how the match is played out depending on when the final rain interruption has come.

Courtesy of the ICC playing conditions, here are two working examples:

Example 1: Match starts at 50 overs per side and there is an interruption at 19 overs. Overs are reduced to 46 overs per side and play is about to resume. Before another ball is bowled it rains and play is abandoned for the day. As the match did not resume under the revised overs, the match should continue on the reserve day at the original 50 overs per side with the overs reduced if necessary during the reserve day.

Example 2: The same start as in example 1 i.e. match starts at 50 overs per side and there is an interruption at 19 overs. Overs are reduced to 46 overs per side and play is about to resume. This time, play starts and after an over has been bowled it rains and play is abandoned for the day. As the match has resumed, it is continued on the reserve day at 46 overs per side with the overs further reduced if necessary during the reserve day.

What happens if there's a no result?

If a minimum of 20 overs per side is not possible across the two days and the match is a no result, the team that finished higher in the group stage will progress to the final. That means it would be South Africa who go through to the decider in Ahmedabad on November 19 (where it is very unlikely to rain).