MLB vs WBSC: baseball rule differences

18-inch-square bases. Rule 2.03.

15-inch-square bases. Rule 2.3.

The standard diamond has 90-foot sides; the pitching distance is 60 feet 6 inches. Rule 2.01–2.04.

The standard field uses the same distances, but the U-12 table specifies 75-foot base paths and a 51-foot pitching distance. Rules 2.1–2.4.

Normally 9 innings, subject to early completion or extension. Rule 7.01(a).

U-12: 6; U-15, U-18, U-23 and women: 7; Premier12: 9. These are the listed WBSC events, not every international competition. Appendix A1.2.

After the ninth inning, each half-inning starts with a runner on second. This does not apply to the listed MLB postseason series. Rules 7.01(b), 7.02(g).

The listed events start each extra inning with runners on first and second, no outs, after their scheduled innings. Appendix A1.4.2.

The game-ending provisions do not prescribe a general run-difference rule. Rules 7.01–7.03.

U-12: 15 runs after the losing team bats in 4 innings, or 10 after 5; other listed World Cups: 10 after 5. Championship finals are excluded; bronze games are included. Do not extend these clauses to Premier12. Appendix A1.4.1.

Normally 3 consecutive batters or the end of the half-inning, with injury or illness exceptions. Rule 5.10(g).

Normally the current batter must be retired or reach first, or the side retired; injury or illness can permit earlier replacement. Rule 7.6.2.

4 mound visits per team over regulation; an additional visit in each extra inning cannot carry forward. Defined player visits also count. Rule 5.10(m).

3 free manager, coach or bench-personnel trips, plus an extra trip per three extra innings. Unused regulation trips do not carry into extras. The definition is narrower. Rule 13.11.1.

Rule 5.07(c) prints a 12-second bases-empty delay rule. The supplied PDF does not fully specify the operational MLB pitch timer; do not treat this as its current clock setting.

Rules 13.5–13.6 specify a 20-second clock only with bases empty; the batter has 10 seconds to enter the box.

Four infielders must satisfy the dirt-boundary requirement, with two on each side of second at release. Switching sides during an inning is restricted, with substitution exceptions. Rule 5.02(c).

Apart from pitcher and catcher, fielders may stand anywhere in fair territory. No matching infield-shift restriction appears in this positioning rule. Rule 7.5.3.

A DH may bat for the pitcher; the starting pitcher can also be listed as pitcher/DH. Rule 5.11.

A DH and pitcher/DH are also provided for. The event appendix excludes the DH at the U-12 World Cup. Rule 9.3; Appendix A1.1.

The general specification is one piece of solid wood, with approval provisions for experimental bats. Rule 3.02.

Material depends on the event: wood for U-18, U-23 and Premier12; approved non-wood options exist for younger categories and women. Rules 3.2; Appendix A1.7.

The league may limit warm-up pitch numbers or duration; emergency replacements may receive additional pitches at the umpire’s discretion. Rule 5.07(b).

Up to 8 warm-up pitches within the allotted interval; the rule also specifies timing and penalties for relief-pitcher preparation. Rule 13.4.

Game protests are not permitted, including claims that a rule was misapplied. Rule 7.04.

National federations should provide a regular-season procedure for protests about rule application, not judgment calls. Deadlines and outcome conditions apply. Rule 7.12.

Base coaches must wear protective helmets. Major League hitters use at least a single ear-flap helmet. Rule 3.08.

The event appendix recommends coach skull caps; double ear-flap helmets are mandatory for U-18 and younger. Appendix A1.3.

The supplied book mentions Replay Review but does not provide a complete challenge protocol or allowance. Do not infer an MLB allowance from this PDF. Rule 5.10(m)(2)(E).

The review appendix grants one challenge, retained if overturned; each team has one challenge in extra innings. Only listed calls qualify. Appendix B1–B2.