In baseball or softball, a strikeout or strike-out (denoted by SO or K) occurs when a batter receives three strikes during his time at bat. A strikeout is a statistic recorded for both pitchers and batters. Pitchers want to throw as many strikeouts as possible, while batters attempt to minimize striking out themselves.

Although strikeouts are associated with dominance on the part of the pitcher, it is recognized that the style of swing that generates a home run also leaves batters somewhat susceptible to striking out. Some of the greatest home run hitters of all time – such as Reggie Jackson and Sammy Sosa – were notorious for striking out.

A pitcher receives credit for (and a batter is charged with) a strikeout on any third strike, but a batter is out only if one of the following is true:

Thus, it is possible for a batter to strike out, but still become a runner and reach base safely if the catcher is unable to catch the third strike cleanly, and he then does not either tag out the batter or force him out at first base. In Japan, this is called furinige (振り逃げ^?), or "swing and escape." In Major League Baseball, it is known as an uncaught third strike. As a result, pitchers have occasionally been able to record four strikeouts in one half-inning.

Yu Darvish (also spelled Yū Darvish) (Japanese: ダルビッシュ 有; born August 16, 1986, in Habikino, Osaka) is a Japanese starting pitcher for the Texas Rangers.

Darvish pitched in the 2008 Beijing Olympics as well as the 2009 World Baseball Classic as a member of the Japanese national team. He was considered by many to be the best pitcher in Japanese professional baseball prior to his arrival in Major League Baseball in 2012.

Darvish was born in Habikino, Osaka, to an Iranian father, Farsad Darvishsefat, and a Japanese mother, Ikuyo. His parents met at Eckerd College, a liberal arts school in St. Petersburg, Florida, where his father played for the college soccer team. His grandfather was a travel agent in Iran, and sent Farsad to the United States in 1977 to attend high school in Berkshire County, Massachusetts, where he also raced competitively in motocross.

Darvish began playing baseball in second grade and led his team to the quarter-finals of the national tournament as well as a third-place finish in the international tournament as a member of the Habikino Boys. He was scouted by over 50 high schools while in junior high, but opted to attend Tohoku High School, a noted baseball powerhouse that produced players such as former Seattle Mariners and Yokohama BayStars closer Kazuhiro Sasaki and current Arizona Diamondbacks reliever Takashi Saito, in northern Sendai.

Lynn Nolan Ryan, Jr. (born on January 31, 1947), nicknamed "The Ryan Express", is a former Major League Baseball pitcher. He is currently principal owner, president and CEO of the Texas Rangers.

During a major league record 27-year baseball career, he pitched in 1966 and from 1968 to 1993 for four different teams: the New York Mets, California Angels, Houston Astros, and Texas Rangers. He was inducted into the Baseball Hall of Fame in 1999.

Ryan, a hard-throwing right-handed pitcher, threw pitches that were regularly recorded above 100 miles per hour (160.93 km/h). The high velocity remained throughout his career, even into his 40s. Ryan was also known to throw a devastating 12–6 curveball at exceptional velocity for a breaking ball.

While his lifetime winning percentage was a relatively pedestrian .526, Ryan was an eight-time MLB All-Star, and his 5,714 career strikeouts rank first in baseball history by a significant margin. He leads the runner-up, Randy Johnson, by 839 strikeouts. Similarly, Ryan's 2,795 bases on balls lead second-place Steve Carlton by 962—walking over 50% more hitters than any other pitcher in Major League history. Other than Jackie Robinson (whose number was retired by the entire MLB), Ryan is currently the only major league baseball player to have his number retired by at least 3 different teams: the Angels, Astros, and Rangers.

Richard Nelson Henley "Rickey" Henderson (born December 25, 1958) is an American former Major League Baseball left fielder who played for nine teams from 1979 to 2003, including four stints with his original team, the Oakland Athletics. Nicknamed The Man of Steal, he is widely regarded as the sport's greatest leadoff hitter and baserunner. He holds the major league records for career stolen bases, runs scored, unintentional walks and leadoff home runs. At the time of his last major league game in 2003, the ten-time American League (AL) All-Star ranked among the sport's top 100 all-time home run hitters and was its all-time leader in bases on balls. In 2009, he was inducted to the Baseball Hall of Fame on his first ballot appearance.

In addition to the career steals record, Henderson also holds the single-season record for stolen bases (130 in 1982) and is the only player in AL history to steal 100 bases in a season, having done so three times. His 1,406 career steals is 50% higher than the previous record of 938 by Lou Brock. Henderson is the all-time stolen base leader for the Oakland A's and previously held the New York Yankees' franchise record from 1988-2011. He was among the league's top ten base stealers in 21 different seasons.

Kerry Lee Wood (born June 16, 1977) is a former Major League Baseball pitcher. He played for the Chicago Cubs, Cleveland Indians and New York Yankees. Wood recorded over 200 strikeouts in four out of his first five seasons, with a high of 266 in 2003 and is the co-holder the MLB record for strikeouts in a single game (20), earning himself the nickname Kid K. He was a two-time National League All-Star and pitched in the post-season five times in a career that spanned 15 seasons. Wood was the 1998 National League Rookie of the Year.

Wood transitioned to a relief pitcher in 2007 due to struggling with injuries throughout his career. He has been placed on the disabled list 14 times in 13 major league seasons, including missing the entire 1999 season due to Tommy John surgery. After a slow start to the 2012 season, Wood retired on May 18th, 2012.

Wood became a phenomenon while attending MacArthur High School in Irving, Texas, for his first three seasons of high school baseball. He continued his domination of batters at Grand Prairie High School in his final season as a high school player.