T20 (Twenty20)

T20 is the shortest professional format. Each side bats for at most 20 overs, and a match takes around three hours.

The rules that shape it are simple. No bowler may bowl more than four overs, so a captain needs at least five bowling options. The first six overs are the powerplay, when only two fielders may stand outside the 30-yard circle. After that, five may. Every wide and no-ball costs a run and must be re-bowled, and a no-ball also gives the batter a free hit. A tied match in most competitions goes to a super over.

Because there are so few balls, the value of each one is high. Batters accept a much greater risk of dismissal for a higher scoring rate, which is why strike rate matters more than batting average here. Bowlers are judged on economy as much as wickets, and captains plan an innings in three phases: powerplay, middle overs and death overs.

The format began in English domestic cricket in 2003 and now underpins the biggest franchise leagues in the world, whose seasons revolve around a player auction or draft.

In Masterstroke: every club season is a T20 campaign of fourteen league matches, with four-over spells, impact substitutes and a chase equation the batters actually read.