The follow-on: why a team bats twice in a row
Understand the optional follow-on, first-innings leads and the change to normal innings order.
It changes the order, not the score
The follow-on belongs to a two-innings match. It lets the side batting first require its opponent to bat again after the opponent's first innings, rather than the leading side immediately beginning its own second innings. It is an option, not an automatic consequence of trailing.
The scoreboard can therefore show the same team beginning a new innings straight after its previous one ended. That is not a duplicate innings or a reset of the team's earlier score. Read the innings number as well as the team name.
The lead requirement depends on duration
MCC Law14 gives a 200-run threshold in a match of five days or more, 150 for three or four days, 100 for two days, and 75 for one day. These are leads after the relevant first innings, not targets for the next innings.
The Law also covers a lost first day and the number of days remaining when play starts. Check the actual match conditions before applying a threshold from memory. A shorter multi-day fixture is not automatically governed by the five-day number.
The captain chooses
The leading captain must notify the opposing captain and umpires when taking the option, and the notified decision cannot be changed. A large lead alone does not tell you whether the follow-on was enforced.
Watch the innings label and match status on ScoreZaap. A team following on still has its second innings to play; the first-innings deficit is not already a final losing margin. This guide explains the order of play, not a recommendation about whether a captain should enforce the option in a particular match.