Editing Home run (section)

==History==
[[Image:MLB HR and SB rates.png|thumb|right|upright=2|Graph depicting the yearly number of home runs (blue line), and stolen bases (pink line) per MLB game from 1900 to 2008.]]
In the [[History of baseball in the United States|early days of the game]], when the ball was less lively and the ballparks generally had very large outfields, most home runs were of the inside-the-park variety. The first home run ever hit in the [[National League (baseball)|National League]] was by Ross Barnes of the Chicago White Stockings (now known as the [[Chicago Cubs]]), in 1876. The home "run" was literally descriptive. Home runs over the fence were rare, and only in ballparks where a fence was fairly close. Hitters were discouraged from trying to hit home runs, with the conventional wisdom being that if they tried to do so they would simply fly out. This was a serious concern in the 19th century because in baseball's early days, a ball caught after one bounce was still an out. The emphasis was on place-hitting and what is now called "manufacturing runs" or "small ball".

The home run's place in baseball changed dramatically when the [[live-ball era]] began after World War I. First, the materials and manufacturing processes improved significantly, making the now-mass-produced, cork-centered ball somewhat more lively. Batters such as [[Babe Ruth]] and [[Rogers Hornsby]] took full advantage of rules changes that were instituted during the 1920s, particularly the prohibition of the [[spitball]], and the requirement that balls be replaced when worn or dirty. These changes resulted in the baseball being easier to see and hit, and easier to hit out of the park. Meanwhile, as the game's popularity boomed, more outfield seating was built, shrinking the size of the outfield and increasing the chances of a long fly ball resulting in a home run. The teams with the sluggers, typified by the [[New York Yankees]], became the championship teams, and other teams had to change their focus from the "inside game" to the "power game" in order to keep up.

Before {{mlby|1931}}, Major League Baseball considered a fair ball that bounced over an outfield fence to be a home run.<ref name=Bounce/> The rule was changed to require the ball to clear the fence on the fly, and balls that reached the seats on a bounce became automatic doubles (often referred to as a [[ground rule double]]). The last "bounce" home run in MLB was hit by [[Al López]] of the [[1930 Brooklyn Robins season|Brooklyn Robins]] on September 12, 1930, at [[Ebbets Field]].<ref name=Bounce>{{cite web |url=https://baseballhall.org/discover/inside-pitch/al-lopez-hits-last-bounce-home-run |title=Future Hall of Famer Al López Hits the Last 'Bounce' Home Run in Big League History |website=baseballhall.org |first=Connor |last=O'Gara |access-date=April 16, 2020 |archive-date=October 16, 2021 |archive-url=https://web.archive.org/web/20211016175844/https://baseballhall.org/discover/inside-pitch/al-lopez-hits-last-bounce-home-run |url-status=dead }}</ref> A carryover of the old rule is that if a player deflects a ball over the outfield fence in fair territory without it touching the ground, it is a home run, per MLB rule 5.05(a)(9).<ref name=RULES/>{{rp|23}} Additionally, MLB rule 5.05(a)(5) still stipulates that a ball hit over a fence in fair territory that is less than {{convert|250|ft|m}} from home plate "shall entitle the batter to advance to second base only",<ref name=RULES/>{{rp|22}} as some early ballparks had short dimensions.

[[File:Polo Grounds 1917.jpg|thumb|left|upright|The [[Polo Grounds]] left field foul line with guide rope, as seen from the upper deck, 1917]]

Also until circa 1931, the ball had to go not only over the fence in fair territory, but it had to land in the [[bleacher]]s in fair territory or still be visibly fair when disappearing from view. The rule stipulated "fair when last seen" by the [[umpire (baseball)|umpires]].<ref>{{cite news |url=https://www.newspapers.com/clip/111016451/babe-ruth-gained-four/ |title=Babe Ruth Gained Four |newspaper=[[The Kansas City Star]] |page=12 |date=January 25, 1921 |accessdate=October 9, 2022 |via=newspapers.com}}</ref> Photos from that era in ballparks, such as the [[Polo Grounds]] and [[Yankee Stadium (1923)|Yankee Stadium]], show ropes strung from the foul poles to the back of the bleachers, or a second "foul pole" at the back of the bleachers, in a straight line with the foul line, as a visual aid for the umpire. Ballparks still use a visual aid much like the ropes; a net or screen attached to the foul poles on the fair side has replaced ropes. As with American football, where a touchdown once required a literal "touch down" of the ball in the end zone but now only requires the "breaking of the [vertical] plane" of the goal line, in baseball the ball needs only "break the plane" of the fence in fair territory (unless the ball is caught by a player who is in play, in which case the batter is called out).

[[Babe Ruth]]'s 60th home run in 1927 was somewhat controversial because it landed barely in fair territory in the stands down the [[right field]] line. Ruth lost many home runs in his career due to the when-last-seen rule. Bill Jenkinson, in ''The Year Babe Ruth Hit 104 Home Runs'', estimates that Ruth lost at least 50 and as many as 78 in his career due to this rule.

Further, the rules once stipulated that an over-the-fence home run in a sudden-victory situation would only count for as many bases as was necessary to "force" the winning run home. For example, if a team trailed by two runs with the bases loaded, and the batter hit a fair ball over the fence, it only counted as a triple, because the runner immediately ahead of him had technically already scored the game-winning run. That rule was changed in the 1920s as home runs became increasingly frequent and popular. Babe Ruth's career total of 714 would have been one higher had that rule not been in effect in the early part of his career.

In the 2020s, it has become increasingly popular for Major League teams to celebrate home runs using some sort of prop.<ref>{{cite web|url=https://www.mlb.com/news/ranking-2023-home-run-celebrations |title=Ranking 2023 home run celebrations |first=Will |last=Leitch |website=[[MLB.com]] |access-date=May 21, 2023}}</ref> For example, allowing the player to wear or hold an item, such as a hat, helmet, jacket, sword, or trident.