Four teams, six matches, three rounds: the group-stage format the World Cup made famous, and the most common pool size in every sport's tournament weekend. Everyone plays three real games; the top two usually advance.
4 teams · 6 matches · 3 rounds
Six matches arrange perfectly into three rounds of two simultaneous games:
Every team plays once per round. With two surfaces the whole pool takes three time slots; with one, six. This is why tournament directors love pools of four — the math is clean and no team ever sits idle while their group plays.
The classic use: split a bigger field into pools of 4, run this in each pool, advance the top 2 into a knockout bracket. Eight teams = two pools + a 4-team single elim; sixteen = four pools + an 8-team bracket. Make one round robin bracket per pool and one elim bracket for the knockout — every bracket gets its own share link.
Announce before the first serve/pitch/tip: what breaks ties (head-to-head, then differential is standard) and whether the last round is played simultaneously. The World Cup plays final group games at the same time for a reason — it stops teams from playing to a known result.
With three games each, 2-1 records pile up. Head-to-head resolves two-way ties directly from the grid. The ugly case is the three-way 2-1 tie (each beat the next in a circle) — only point differential breaks that, so keep score margins somewhere, not just winners.