If you don't believe me that baseball is derived from the British schoolgirls' game of rounders - rather than just being similar to it - here's what Wikipedia says about rounders. In fact, we used to call rounders "base-ball" -
Rounders is a British game for schoolgirls (without helmets), though the Americans now have it as their national sport.
Rounders is a sport which originated in Great Britain and Ireland. The game is regulated by the Gaelic Athletic Association (GAA) in Ireland and the National Rounders Association (NRA) in England. Both regulating bodies operate a slightly different, although broadly similar, game-play and culture. Competitions are held between teams from both traditions with games alternating between codes, often with one version being played in the morning and the other being played in the afternoon.
Game-play centres around innings where teams alternate at turns being batters and fielders. A maximum of nine players are allowed to play in fielding positions at one time. Points ("rounders") are scored by the batting team by completing a circuit around the field through four bases/posts without being put 'out' - for example, by a ball they batted being 'caught-out' or touching a tagged base/post.
The sport is very old and it has been documented as early as the seventeenth century. The earliest nationally formalised rules of play were devised by the GAA in Ireland in 1884. Liverpudlian and Scottish associations were formed in 1889. The NRA were not formed until 1943.
Baseball (both the "New York game" and the now-defunct "Massachusetts game") as well as softball evolved from rounders (see origins of baseball) and bear a striking resemblance to the GAA version of the game. In fact, the earliest literary mention of rounders calls the game "base-ball." Rounders is now played on all levels from school-level to internationals.
Players: Three substitutes may be made during play to the list of field players. There is no limit for the number of batters a team may list.
Equipment: The ball (sliotar) circumference is 22.7-25.5 cm (9"-10") and bats may be 70-110 cm (27"-43") long and up to 22 cm (8.6") in diameter. There is no limit on bat-weight for the GAA game. Bases are normally marked with temporary square mats 64 cm (28") wide for home-base and the pitchers stand and 46 cm (18") wide for all others.
Batting: Each batsman is entitled to three good balls. A batsman must try to hit good balls bowled to him/her but need not run on a hit. If s/he hits a ball that would otherwise be considered 'bad', the ball is then considered to be 'good.' If, on the his/her first or second good ball, s/he hits a ball into the foul ground or hits the ball but does not run then it is considered a 'dead' ball and other batsmen men may not advance. If a batter receives three bad balls then a 'walk-on' is called and all batsmen may advance one base. The batter may run on any ball except a 'dead' ball.
A batsman is out if:
the catcher catches and holds the third good ball bowled to him/her
s/he strikes a ball into the foul ground on his/her third good ball
s/he obstructs the pitchers or catchers view for a second time (s/he will be warned on the first instance)
s/he comes into contact with a fielder carrying the ball
s/he touches a base that has been 'tagged' by another fielder carrying the ball (s/he may return to the previous base before touching it, if that base is still unoccupied)
s/he attempts to occupy a base occupied by another batsman (with the exception of 1st base, which another batsman must vacate to make way for the current batter)
Batsmen must run in straight lines between bases and fielders may not obstruct their way or stand on bases. Not obeying this rule is considered unsporting behaviour and may result in up to two bases being awarded to the batting team or a batter being sent out. Normally, one batsman may not overtake another while running between bases, although there are exceptions to this rule.
Five to seven innings constitute a game, depending on the level of the match. Each batting team's inning continues until three outs are made.
[edit]
NRA Specific Rules
Diagram of an NRA standard rounders pitch.The rules of rounders are regulated by the National Rounders Association in England[2]. Games played under these rules use smaller bats, balls and are played on a smaller pitch (see diagram) compared to GAA games. The NRA rules also differ most from baseball or softball: bases are marked with long poles, which batsmen must keep in contact with and fielders must 'stump,' and only one 'good' ball need normally be thrown before a batter must run. 'Half-rounders' are also counted in scoring.
Players: The fielding team must field at a minimum six players. The total number of players on a team is limited to fifteen.
Equipment: The ball circumference must be 7.5 inches (19 cm) and the bat no more than 18" (460 mm) in length and 6.75" (170 mm) in diameter. The NRA places a weight-limit of 13 ounces (370g) on the bat. Bases are marked with poles. These poles need to be as long as brooms and the bases need to be sturdy enough to hold them upright.
Batting: If a ball is good, a batsman must try to hit it and regardless of whether s/he hits the ball, the batter must run on a good ball. If the ball is hit into the backward area, the batsman may not pass first post until the ball is returned to the forward area. If the batter hits a no-ball, s/he may not be caught-out or stumped at the first post. Batsmen may run, if s/he chooses, on 'no-balls.' Each batsman except the last in each inning is entitled to receive one good ball; the last batsman is entitled to receive three unless caught out.
A half-rounder is scored if:
fourth post is reached and touched before the next ball is bowled without hitting the ball
second post is reached and touched before next ball is bowled after hitting the ball
obstruction by a fielder/batter
two consecutive no-balls to the same batter
A batsman is out if:
s/he runs inside the posts
s/he is not in contact with a post (using his hand or stick) while the bowler is preparing to bowl
s/he is not in contact with a post and the next post is stumped
s/he puts a foot outside the front or back of the batting square before swinging at a good ball
s/he overtakes another runner
Two innings constitute a game. Each batting team's inning continues until nine outs are made or the numbered innings is over.
wikipedia.org
So the Americans didn't invent baseball. The British did hundreds of years ago, but the Yanks didn't realise that we intended it to be played by little girls.
And it's not only the United States that has a British schoolgirls' game as their national sport. Canada's national sport - ice hockey - bears an uncanny resemblance to hockey, and basketball - invented in Canada - looks too much like netball.
Netball is a girls' game - except in North America where they call it "basketball".