MasterstrokeMatch play and rules
Follow-on
If the side batting second trails by 200 or more, it can be made to bat again immediately. A powerful weapon that comes with a tired-bowlers tax.
The follow-on lets a captain make the opposition bat again immediately if they finished their first innings 200 or more runs behind.
Normally the two sides alternate innings. If the team batting second falls 200 runs short of the first-innings total in a five-day match, the captain of the side that batted first may enforce the follow-on, sending them straight back in. A side that follows on must overtake the deficit just to make its opponents bat again, and matches won from that position are famous precisely because they are rare.
Whether to enforce it is a real decision. The case for is time: it removes a whole innings from the clock and makes a draw much less likely. The case against is fatigue. Your bowlers have just spent a day or more in the field, the pitch may be at its best for batting, and batting last on a wearing surface is a risk. Many modern captains decline the follow-on when they have a large lead and time in hand, bat quickly, and declare instead.
In Masterstroke: the follow-on is yours to enforce or decline, and overnight recovery decides how much your bowlers have left.