Koji Yamamoto (baseball, born 1946)

1.1. Birth and Childhood

Yamamoto was born on October 25, 1946, in Itsukaichi-cho, Saeki-gun, Hiroshima Prefecture (now Saeki-ku, Hiroshima City). His father was a former military officer who later worked in construction after World War II. Yamamoto is a second-generation atomic bomb survivor, as his mother, two older brothers, and older sister were exposed to the atomic bombing of Hiroshima. His parents were avid fans of the Hiroshima Toyo Carp, and from a young age, they often took him by ferry across the Ōta River to the Hiroshima Prefectural Baseball Stadium, the Carp's home field at the time. He had the opportunity to witness the play of key Hiroshima players firsthand, including ace pitcher Ryohei Hasegawa, cleanup hitter Makoto Kozuru, and speedster Jiro Kanayama. Yamamoto particularly admired Kozuru, often imitating his batting form, which fueled his dream of becoming a professional baseball player.

1.2. Education

Driven by his aspiration to play in the Koshien Tournament and his family's desire for him to pursue higher education, Yamamoto chose to attend Hiroshima Prefectural Hatsukaichi High School, a school with no notable baseball reputation. Upon joining the baseball team, he immediately became the ace pitcher and cleanup hitter. During his high school career, he faced talented contemporary players such as Kazumi Takahashi and Kunikazu Ogawa, and also played against Tomi Ushirohara, who was one year his senior. In his third year, as team captain, he led Hatsukaichi High deep into the summer Koshien prefectural qualifiers, but they ultimately lost 1-9 to the strong Koryo High School, which featured pitcher Kazuaki Kawamoto (who later declined a first-round draft pick by the Sankei Swallows).

Kazuto Tsuruoka, then manager of the Nankai Hawks, scouted Yamamoto at Hatsukaichi High. Tsuruoka, a Hosei University alumnus, recognized Yamamoto's batting potential but felt he wasn't ready for professional baseball. He advised Yamamoto to attend university, stating, "He's not good enough as a pitcher, but he's good at batting. However, it will take several years for him to be effective in the top league." Following this advice, Yamamoto enrolled in the English Literature Department of Hosei University in 1965.

He initially joined the Hosei University baseball team as a pitcher. However, with 70 to 80 freshmen joining the team, he struggled to stand out and was not part of the elite training group that included future star Kōichi Tabuchi. For a year and a half, he served primarily as a batting practice pitcher. After a ball hit his right arm, forcing him to rest for a week, coach Reiichi Matsunaga noticed his batting ability and began giving him intensive individual training. Yamamoto was then converted to an outfielder, along with Masaru Tomita. He established himself as a regular in the fall of his second year and was promoted to the cleanup spot. From then on, Yamamoto, along with Tabuchi and Tomita, became known as the "Hosei Trio" (法政三羽ガラス_{Hōsei Sanbagarasu}^Japanese), a formidable force that contributed significantly to Hosei's golden era in Tokyo Big6 Baseball. During his university career, Hosei won three league championships, and in 1968, they won the All-Japan University Baseball Championship Series. Yamamoto's collegiate statistics included 65 games played, 229 at-bats, 67 hits, a .293 batting average, 8 home runs, and 30 RBI, earning him two Best Nine awards.

Yamamoto harbored a strong desire to join his hometown team, the Hiroshima Carp, despite their reputation as a perennial weak team, having finished in Class B (lower half) 18 times in their 19 years of existence. He dreamed of leading his local team to a championship. Due to his family's concerns about him turning professional, he intended to decline any offers from teams other than Hiroshima and even considered a career as a salaryman if his preferred team did not draft him. In the highly competitive 1968 NPB draft, Yamamoto was selected in the first round by the Hiroshima Toyo Carp, who had the second pick in the preliminary lottery.

2.1. Professional Debut

Yamamoto officially joined the Hiroshima Toyo Carp in 1969, initially wearing uniform number 27. He made his professional debut on April 12, 1969, as the sixth hitter and starting center fielder in the opening game. He quickly established himself as a regular, and by August of his rookie year, he was already being entrusted with cleanup duties. He reached the qualifying at-bats, finishing the season with a .240 batting average. Throughout his rookie season, he experienced playing in all batting positions, from first to ninth. In 1970, he primarily batted third, and in 1971, he was mostly the fifth hitter. By 1972, he was often used as the leadoff or fifth hitter, showcasing his versatility. Over these early years, he steadily improved under the guidance of various coaches, including Rikuo Nemoto, Toshiharu Ueda, Junzo Sekine, and Tatsuro Hirooka. In 1971, following the retirement of Kazuhiro Yamauchi, Yamamoto inherited the iconic uniform number 8, which he wore for the remainder of his playing career.

2.2. "Mr. Red Helmet" Era

In the 1974 season, Yamamoto primarily batted third, achieving strong results with a .275 batting average, 28 home runs (5th in the league), and 74 RBI. On May 23, 1974, he hit a grand slam against Senichi Hoshino of the Chunichi Dragons. On August 27, he hit his first career walk-off home run against Keiji Asano of the Yakult Swallows. During the offseason that year, influenced by a fortune teller who advised that the name "Koji" (浩司) was not suitable for a competitor, he changed the kanji in his registered name from "浩司" to "浩二" (both pronounced Koji).

The 1975 season marked a turning point for Yamamoto and the Hiroshima Carp. He became the team's regular cleanup hitter from late June. In the first game of the 1975 All-Star Game, he batted third for the Central League, forming a powerful cleanup with Sadaharu Oh (fourth) and Kōichi Tabuchi (fifth). He and Sachio Kinugasa (sixth) famously hit back-to-back home runs in two consecutive at-bats. Yamamoto maintained excellent form throughout the season, recording a .319 batting average, 30 home runs, 84 RBI, and 24 stolen bases. He achieved his first career .300+ batting average and 30+ home run season, winning his first batting title. His outstanding performance was instrumental in the Carp's first-ever league championship, and he was subsequently named the Central League MVP. On October 15, 1975, as the Carp clinched the league title, Yamamoto was visibly emotional, shedding tears of joy. It was also in this season that the Hiroshima Carp adopted their signature red helmets, and Yamamoto's iconic nickname, "Mr. Red Helmet" (ミスター赤ヘル_{Misutā Akaheru}^Japanese), became firmly established among the fans, solidifying his status as a local hero.

After a slight dip in performance in 1976, Yamamoto returned strong in 1977, hitting 44 home runs and 113 RBI, both ranking second in the league behind Sadaharu Oh. From 1977, he embarked on an extraordinary streak of five consecutive seasons with 40 or more home runs, a record in Japan paralleled only by Sadaharu Oh. He led the league in home runs four times (1978, 1980, 1981, and 1983) and was the RBI champion for three consecutive years (1979-1981). His defensive excellence was equally remarkable; he received the Mitsui Golden Glove Award for ten consecutive years from 1972 to 1981, setting a Central League record for outfielders in both total awards and consecutive wins. This period firmly established Yamamoto as one of NPB's premier power hitters and all-around players.

2.3. Player Characteristics

Kōji Yamamoto was renowned for his exceptional all-around skills, combining formidable hitting prowess with outstanding defensive capabilities and surprising speed for a power hitter.

2.4. Major Awards and Titles

Kōji Yamamoto's illustrious playing career was marked by numerous individual accolades and titles, reflecting his dominance as both a hitter and an outfielder.

• Batting Champion: 1 time (1975)
• Home Run King: 4 times (1978, 1980, 1981, 1983)
  • This is a Central League record for right-handed batters.
• RBI King: 3 times (1979-1981)
• Most Times on Base: 3 times (1979, 1980, 1983)
• Most Valuable Player (MVP): 2 times (1975, 1980)
• Best Nine: 10 times (1975, 1977-1984, 1986)
  • His 10 awards as an outfielder are tied for second all-time, and a Central League record.
  • His 8 consecutive awards are tied for second all-time and the longest in the Central League (tied with Hideki Matsui).
• Diamond Glove Award: 10 times (1972-1981)
  • His 10 career awards and 10 consecutive awards as an outfielder are both Central League records.
  • His 10 consecutive awards are tied for second all-time (tied with Koji Akiyama and Ryosuke Kikuchi).
  • In 1972, he was one of the first outfielders in Central League history to receive the award, alongside Shigeru Takada and Isao Shibata.
• Japan Series Fighting Spirit Award: 1 time (1975)
• Japan Series Excellent Player Award: 1 time (1984)
• Monthly MVP: 5 times (August 1975, August 1978, June 1980, April 1983, April 1986)
• All-Star Game MVP: 2 times (1975 Game 1, 1979 Game 3)
• Hochi Pro Sports Award: 1 time (1987)
• Hiroshima Prefectural Honorary Citizen Award: (1987)
• Baseball Hall of Fame (Player Category): (2008)

2.5. Career Milestones and Records

Kōji Yamamoto achieved numerous significant milestones and set several records throughout his distinguished 18-year career, solidifying his place among the all-time greats of Japanese professional baseball.

; Milestone Records

• 100 Home Runs: June 13, 1974, vs. Hanshin Tigers (Hanshin Koshien Stadium), off Yutaka Enatsu - 79th player in NPB history.
• 150 Home Runs: May 7, 1976, vs. Taiyo Whales (Kawasaki Stadium), off Akira Tanaka - 41st player in NPB history.
• 1,000 Games Played: October 5, 1976, vs. Hanshin Tigers (Hiroshima Municipal Stadium) - 187th player in NPB history.
• 1,000 Hits: May 22, 1977, vs. Yomiuri Giants (Korakuen Stadium), off Shoji Sadaoka - 101st player in NPB history.
• 200 Home Runs: August 11, 1977, vs. Hanshin Tigers (Hiroshima Municipal Stadium), off Norikazu Miyata - 27th player in NPB history.
• 250 Home Runs: September 6, 1978, vs. Chunichi Dragons (Nagoya Stadium), off Hisato Aoyama - 15th player in NPB history.
• 300 Home Runs: April 8, 1980, vs. Taiyo Whales (Hiroshima Municipal Stadium), off Kazuhiko Endo - 12th player in NPB history.
• 1,500 Hits: September 7, 1980, vs. Hanshin Tigers (Hiroshima Municipal Stadium), off Kazuyuki Yamamoto - 40th player in NPB history.
• 1,500 Games Played: September 11, 1980, vs. Chunichi Dragons (Nagoya Stadium) - 64th player in NPB history.
• 350 Home Runs: April 28, 1981, vs. Chunichi Dragons (Hiroshima Municipal Stadium), off Jun Misawa - 10th player in NPB history.
• 3,000 Total Bases: June 18, 1981, vs. Yomiuri Giants (Hiroshima Municipal Stadium), off Shoji Sadaoka - 16th player in NPB history.
• 1,000 RBI: August 2, 1981, vs. Chunichi Dragons (Hiroshima Municipal Stadium), off Yujiro Miyako - 13th player in NPB history.
• 1,000 Runs Scored: August 20, 1981, vs. Yomiuri Giants (Hiroshima Municipal Stadium) - 14th player in NPB history.
• 400 Home Runs: June 5, 1982, vs. Yomiuri Giants (Hiroshima Municipal Stadium), off Yoshitaka Katori - 8th player in NPB history.
• 300 Doubles: July 14, 1982, vs. Taiyo Whales (Yokohama Stadium), off Hiroaki Takeuchi - 21st player in NPB history.
• 3,500 Total Bases: May 18, 1983, vs. Chunichi Dragons (Nagoya Stadium), off Tatsuo Komatsu - 11th player in NPB history.
• 450 Home Runs: October 3, 1983, vs. Yomiuri Giants (Hamamatsu Stadium), off Tsuneo Horiuchi - 7th player in NPB history.
• 2,000 Hits: May 5, 1984, vs. Yomiuri Giants (Korakuen Stadium), off Hiromi Makihara - 19th player in NPB history.
• 2,000 Games Played: August 1, 1984, vs. Taiyo Whales (Hiroshima Municipal Stadium) - 19th player in NPB history.
• 1,000 Strikeouts: May 5, 1985, vs. Taiyo Whales (Hiroshima Municipal Stadium), off Kazuhiko Endo - 9th player in NPB history.
• 350 Doubles: June 5, 1985, vs. Taiyo Whales (Hiroshima Municipal Stadium), off Hiroshi Sekine - 14th player in NPB history.
• 4,000 Total Bases: June 13, 1985, vs. Hanshin Tigers (Hiroshima Municipal Stadium), off Hiroaki Ito - 8th player in NPB history.
• 500 Home Runs: July 26, 1985, vs. Chunichi Dragons (Nagoya Stadium), off Tadashi Sugimoto - 4th player in NPB history.

; Other Records

• 500 Home Runs and 200 Stolen Bases: Achieved on July 26, 1985 - only the second player in NPB history to achieve this feat (after Isao Harimoto; Sachio Kinugasa also achieved this).
• Seasons with 40+ Home Runs: 5 times (1977-1981) - tied for 3rd all-time.
• Seasons with 30+ Home Runs: 9 times (1975, 1977-1984) - tied for 3rd all-time.
• Seasons with 100+ RBI: 6 times (1977-1981, 1983) - 3rd all-time.
• Consecutive Seasons with 40+ Home Runs: 5 years (1977-1981) - 2nd all-time.
• Consecutive Seasons with 30+ Home Runs: 8 years (1977-1984) - 3rd all-time.
• Consecutive Seasons with 20+ Home Runs: 13 years (1974-1986) - tied for 3rd all-time.
• Consecutive Seasons with 100+ RBI: 5 years (1977-1981) - tied for 3rd all-time.
• Consecutive Seasons with 100+ Hits: 17 years (1970-1986) - tied for 4th all-time, a Hiroshima Carp team record.
• Cycle Hit: April 30, 1983, vs. Hanshin Tigers (Hanshin Koshien Stadium) - 36th player in NPB history.
• Consecutive Hits: 9 (July 6-8, 1972).
• Consecutive Error-Free Chances (Outfielder): 302 (April 5 - September 24, 1975) - Central League record for outfielders.
• Consecutive Games Played: 872 (October 22, 1976 - August 28, 1983) - 11th all-time.
• Reached Qualifying At-Bats Every Season: From his debut year to his retirement year (1969-1986).
• Career Grand Slams: 11 - tied for 9th all-time.
• Career Slugging Percentage: .5416 (1969-1986) - 10th all-time.
• Career Outfielder Putouts: 4,637 - 2nd all-time, Central League record.
• Career Outfielder Assists: 154 - 2nd all-time, Central League record.
• Career Outfielder Chances: 4,830 - 2nd all-time, Central League record.
• 1,000 Hits at a Single Ballpark: Hiroshima Municipal Stadium.
• All-Star Game Appearances: 14 times (1973-1986).
• All-Star Game Career Batting Average: .316 (among players with 100+ at-bats) - 3rd all-time.
• All-Star Game Career Home Runs: 14 - 1st all-time.
• All-Star Game Career RBI: 27 - tied for 3rd all-time.

2.6. Team Success

Kōji Yamamoto was a central figure in the Hiroshima Toyo Carp's golden era, leading the team to unprecedented success and multiple championships.

In 1975, Yamamoto's MVP season, he led the Carp to their first-ever Central League championship. Although they fell short in the 1975 Japan Series against the Hankyu Braves, losing in six games, Yamamoto's performance earned him the Japan Series Fighting Spirit Award.

He continued to be the team's offensive cornerstone, and in 1979, the Carp clinched their second Central League title. In the 1979 Japan Series, they faced the Kintetsu Buffaloes. Despite Yamamoto not performing at his peak in the series (3 hits, 2 RBI, 1 HR in 23 at-bats), the Carp emerged victorious, securing their first Japan Series championship. This victory also famously prevented Sadaharu Oh from winning his ninth consecutive RBI title, solidifying Yamamoto's reputation as a formidable slugger.

The following year, 1980, the Carp repeated as Central League champions. In the 1980 Japan Series, they once again faced the Kintetsu Buffaloes. Yamamoto hit two home runs in the series, contributing significantly to the Carp's second consecutive Japan Series title. His powerful offensive partnership with Sachio Kinugasa was famously dubbed the "YK Cannon" (YK砲_YK-hō^Japanese), a duo that hit 86 back-to-back home runs, second only to the "ON Cannon" of Oh and Shigeo Nagashima.

In 1984, Yamamoto, now also serving as a hitting coach, continued to be a key contributor as the Carp won their fourth Central League championship. In the 1984 Japan Series against the Hankyu Braves, Yamamoto delivered crucial hits, including a game-tying RBI single off Hisashi Yamada in Game 1, a go-ahead solo home run off Yoshinori Sato in Game 3, and a game-winning RBI single off Yamada in Game 4. His clutch performances helped the Carp secure their third Japan Series title. For his contributions, he was awarded the Japan Series Excellent Player Award.

2.7. Retirement

Kōji Yamamoto retired from playing professional baseball at the age of 40, following the 1986 season. His final year was a notable one, as he helped the Hiroshima Carp win the Central League championship. In April 1986, he was named the Monthly MVP for his strong performance, batting .377 with 8 home runs and 19 RBI. On August 10, he hit a three-run home run off Shigeru Kuwata of the Chunichi Dragons, marking his 13th consecutive season with 20 or more home runs. On September 11, he hit a walk-off home run against Tadashi Sugimoto, making him the oldest player in Carp history to do so at 39 years and 10 months. The Carp clinched the league title on October 12, 1986, in their 129th game of the 130-game season.

The 1986 Japan Series against the Seibu Lions proved to be Yamamoto's final games as a player. He hit a game-tying home run off Osamu Higashio in Game 1, which would be his last career home run. The series was historic, extending to an unprecedented eighth game, which the Carp ultimately lost to the Lions. Despite the loss, the Hiroshima players and coaching staff gave Yamamoto a farewell *doage* (a celebratory toss) on the field at Hiroshima Municipal Stadium, amidst a thunderous "Koji Call" from the fans. The following day, at his retirement press conference, an emotional Yamamoto declared, "Koji Yamamoto is a happy man."

His career culminated with 536 home runs, a record for a university-educated player in Japanese professional baseball. In recognition of his immense contributions and legendary status, the Hiroshima Carp retired his uniform number 8, making it the first permanent retired number in the team's history. On January 12, 1987, he was awarded the Hiroshima Prefectural Honorary Citizen Award. His official retirement game was held on April 5, 1987, an exhibition match against the Kintetsu Buffaloes at Hiroshima Municipal Stadium. He started as the cleanup hitter and center fielder, going 1-for-2. During the post-game ceremony, he reiterated his gratitude, stating, "I was born in Hiroshima and raised by the Carp. Koji Yamamoto was a happy man."

3.1. Hiroshima Toyo Carp Manager

Upon his retirement as a player, Carp owner Kohei Matsuda offered Yamamoto a player-manager role, which he declined, opting instead to take a break from the field. He spent two years (1987-1988) as a baseball commentator for NHK and a baseball critic for Nikkan Sports.

In 1989, Yamamoto returned to the Hiroshima Carp as manager, signing a five-year contract. He brought in a strong coaching staff, including Tsuyoshi Ohshita as head coach, Kōjirō Ikegaya as pitching coach, and Jitsuo Mizutani as hitting coach. Yamamoto expressed his strong desire for these coaches to join him, stating, "I asked the team to absolutely accept them. I had long wanted Ohshita-san to be the head coach if I became manager. Jin-chan (Mizutani) worked hard on hitting and trained players strictly. Ikegaya was serious and had theories. Everyone worked with my intentions." In his first two seasons, 1989 and 1990, the Carp finished in second place in the Central League. In 1991, he successfully led the team to a Central League championship, but they ultimately lost the Japan Series to the Seibu Lions in a close 3-4 contest. The team's performance declined in 1992, finishing fourth, their first B-class finish in ten years. In 1993, the Carp finished in last place, their first time since 1974, recording a league-worst 14 walk-off losses. Yamamoto took responsibility for the team's poor performance and resigned at the end of the season.

After a seven-year hiatus during which he worked as a baseball commentator for NTV, HTV, and Radio Japan, Yamamoto was asked by the Carp organization to return for a second managerial tenure in 2001. For this second stint, he recruited Makoto Matsubara as chief and hitting coach, and Manabu Kitabeppu as pitching coach. However, his second term was less successful, as the team never finished in the A-class (top three) during his five years. They finished fourth in 2001, then fifth for the next three years, and finally in last place in 2005. Following the 2005 season, he resigned once again due to the team's poor performance. Despite the lack of A-class finishes in his second term, Yamamoto's combined managerial tenure of 10 years (across both stints) made him one of the longest-serving Carp managers, behind only Takeshi Koba and Katsumi Shiraishi (both 11 years). During his managerial career, he was credited with developing key offensive players such as Tomonori Maeda, Kōichi Ogata, and Akira Eto during his first tenure, and Takahiro Arai, Shigeto Shima, and Kenta Kurihara during his second.

3.2. National Team Manager/Coach

After his second managerial stint with the Carp, Yamamoto continued to contribute to Japanese baseball at the national level. In 2007, he was appointed as the defense and base running coach for the Japanese national baseball team under manager Senichi Hoshino for the 2008 Beijing Olympics. The team ultimately finished in fourth place after losses to South Korea and the United States.

On October 10, 2012, Yamamoto was announced as the manager of the Japanese national team for the 2013 World Baseball Classic. His uniform number for the national team was 88. He appointed Osamu Higashio as pitching coach. Yamamoto took on the role despite other potential candidates declining due to low pay. In the 2013 WBC, he led the "Samurai Japan" team to the semifinals, which was Japan's best performance in the tournament up to that point. However, they lost 1-3 to Puerto Rico in the semifinals at AT&T Park in San Francisco, failing to achieve a third consecutive WBC title. Yamamoto notably took full responsibility for a failed double steal attempt in the eighth inning of that game, stating that his "green light" signal to the runners was not a mistake and he had no regrets, even though the base running coach, Takanobu Takashiro, later wrote in his book that he had pushed Yamamoto to allow the play. Takashiro acknowledged that Yamamoto "shouldered all the responsibility, including the staff's failures and the players' mistakes."

4.1. Broadcasting and Commentary

Yamamoto has had a significant career as a baseball analyst and commentator across various media outlets. After his initial retirement as a player, he served as a baseball commentator for NHK and a baseball critic for Nikkan Sports from 1987 to 1988. Following his first managerial tenure with the Hiroshima Toyo Carp (1989-1993), he returned to broadcasting, working as a baseball commentator for NTV, HTV, and Radio Japan from 1994 to 2000. After his second managerial stint (2001-2005), he resumed his role as a baseball commentator for NTV and HTV in 2006, a position he continues to hold. He is also a member of the program review committee for the Sky PerfecTV! JSAT Group.

4.2. Baseball Hall of Fame and Honors

In recognition of his outstanding contributions to Japanese baseball, Kōji Yamamoto was inducted into the Japanese Baseball Hall of Fame in 2008. He is also a distinguished member of the Meikyukai, often referred to as the "Golden Players Club," an exclusive association of Japanese baseball players who have achieved significant career milestones (such as 2,000 hits, 200 wins, or 250 saves). Yamamoto served as the Vice Chairman of the Meikyukai starting in 2010, and then as its Chairman from 2014 to 2022. He currently holds the position of advisor to the club.

6.1. Cultural Significance

Yamamoto's immense popularity and the passionate support he received from fans had a lasting impact on Japanese baseball fan culture. The practice of fans loudly cheering a player's name, known as a "call" (e.g., "Koji Call"), is widely believed to have originated with Yamamoto. Whenever he stepped up to the plate, the Hiroshima Municipal Stadium would erupt with chants of "Koji! Koji!" This phenomenon was then popularized by the media as the "Koji Call," laying the groundwork for player-specific chants common in baseball today. Furthermore, the use of musical instruments, particularly trumpets, in organized cheering sections is also said to have begun during Yamamoto's at-bats. His personal cheer song, using the melody of Waseda University's "Combat March," became highly recognizable.

Even after his retirement, Yamamoto continued to captivate audiences. In a ceremonial first pitch during a 1999 game between the Giants and Carp at Hiroshima Municipal Stadium, he stepped into the batter's box against former Carp pitcher Motoyasu Kinjo. After taking the first pitch, Yamamoto swung at the second and hit a home run into the left-field stands, much to the delight of the crowd and the astonishment of then-Carp manager Mitsuo Tatsukawa.

6.2. Evaluation

Kōji Yamamoto's career is a testament to perseverance and adaptation. Initially a solid but not extraordinary hitter, he transformed into a power-hitting legend, particularly in his 30s. His ability to read pitchers, earning him the nickname "Koji the Reader," became more refined with age. The development of his "wide-angle hitting" to compensate for chronic back pain allowed him to hit home runs to all fields, making him a more complete and feared slugger. This late-blooming characteristic is striking: over 65% of his 536 career home runs (more than 350) and all of his home run and RBI titles were achieved after he turned 30. He is the only university graduate in NPB history to hit over 500 home runs.

Yamamoto's durability was also a key factor in his success. Unlike some contemporaries who struggled with injuries, he played almost every game from his debut season until his retirement, consistently maintaining a high level of performance. This consistency, coupled with his ability to hit for power to the opposite field, was a reason why even the legendary Sadaharu Oh reportedly considered Yamamoto a more formidable rival in home run races than the injury-prone Kōichi Tabuchi.

His impact on the Hiroshima Toyo Carp was profound. He was the cornerstone of the team during its transition from a perennial underdog to a championship contender, leading them to their first league title and multiple Japan Series victories. The retirement of his iconic number 8, the first in Carp history, symbolizes his enduring legacy as "Mr. Red Helmet" and his irreplaceable contribution to the franchise and the sport.

7.1. Bibliography

Yamamoto has authored or co-authored several books:

• Ningen Yamamoto Koji: Kyoso Shakai o Shibutoku Ikiru Tame ni (人間山本浩二-競争社会をしぶとく生きるために, "Koji Yamamoto the Human: For Stubborn Survival in a Competitive Society") (1984, Kotsu Times Sha)
• Eiko no Sebangō 8: Kore ga Ore no Yakyū Jinsei da (栄光の背番号8：これがオレの野球人生だ, "Glorious Uniform Number 8: This is My Baseball Life") (1986, Kotsu Times Sha)
• Koji no Nan'yū Kan'yū (コージのなん友かん友, "Koji's Friends and Acquaintances") (1987, Nikkan Sports Publishing)
• Koji no Akaheru Yakyū (浩二の赤ヘル野球, "Koji's Red Helmet Baseball") (1989, Bungeishunju)
• Yakyū to Hiroshima (野球と広島, "Baseball and Hiroshima") (2015, Kadokawa Shinsho)
• Hiroshima Carp no Ketsumyaku (広島カープの血脈, "The Bloodline of Hiroshima Carp") (2016, KADOKAWA), co-authored with Kenjiro Nomura

7.2. Media Appearances

Yamamoto has made numerous appearances across television, film, radio, and advertising.

; As a Baseball Commentator

• NHK:**
  • NHK Professional Baseball
  • Sunday Sports Special (November 1986 - October 1988)
• Nippon Television/Hiroshima Television:**
  • DRAMATIC BASEBALL (current title)
  • Susume! Sports Genkimaru (Hiroshima Television)

  ; Dramas

  • Saigo no Strike (最後のストライク, "The Last Strike") (Fuji Television, July 28, 2000) - Appeared as a hotel event chief in this drama about Tsuneo Tsuda.

  ; Films

  • BADBOYS (Zenyoku Agency, 2011) - Special appearance.
  • Koinowa: Konkatsu Cruising (角川映画, 2017)

  ; Variety Shows

  • Nakai Masahiro no Black Variety (Nippon Television) - Irregular appearances.
  • Himitsu no Kenmin SHOW (Yomiuri Television)
    • July 14, 2016 - Studio guest with Takashi Tanaka.
    • December 1, 2016 - Special appearance as a neighborhood association head in the Hiroshima episode of the drama segment "Jirei wa Totsuzen ni..."
  • Koji Yamamoto & Joji's Doremi-fa Stadium (歌謡ポップスチャンネル, Kayō Pops Channel) - A special variety program combining baseball and music with Joji Yamamoto, aired March 24, 2019.
  • Professional Baseball Legend Hall (BS Fuji, April 2, 2024)

  ; Radio

  • Wakako Takeda no Pitatto. (ABC Radio, December 4, 2014) - Appeared by phone in the "Yutaka Fukumoto's Where Are They Now? Former Professional Baseball Player Directory" segment.

  ; Commercials (CMs)

  • During Playing Career:**
    • Hiro-un "League Star Baseball Equipment"
    • Masuya Miso (Hiroshima local) - Tagline: "The key is the quality of the 'koji' (fermented rice malt)," with Tsuneo Tsuda making a pun on Yamamoto's name: "Just like our team, right, Koji-san!"
    • Gold Momiji (Hiroshima local) - Tagline: "Gold Momiji is the home run king of sweets."
  • After Retirement:**
    • Ajinomoto "Hon Dashi Iriko Dashi"
    • Sanwa Home (1987)
    • Japan Airlines "Tokyo - Hiroshima Nishi Airport Route"
    • Rohto Pharmaceutical "Shin V-Rohto" (1987-1990)
    • Bridgestone Cycle Bicycles (co-starred with Yuko Asano)
    • Suntory "Malts" - His line "I am not dry" in this commercial was famously featured in the Fuji TV program "Canossa no Kutsujoku" as the "Namamugi Incident."
    • House Foods "Curry is House" campaign (1994) and "Fight with Curry!" campaign (2008) - Both co-starred with Kōichi Tabuchi and Senichi Hoshino.
    • Kowa "Vantelin" (2000s)

    ; Discography

    • 7-inch EP "Hitori" (ひとり, "Alone") (1975, CBS Sony Records SOLB-355)
      • A-side: "Hitori" / B-side: "Ame no Yowa" (雨の夜話, "Night Talk in the Rain")
      • Both songs written by Mieko Arima (lyrics), Shin Kawaguchi (music), Masaaki Jimbo (arrangement).

      ; Appearances in Manga and Anime

      • Baseball Kyō no Uta (漫画, Manga, by Shinji Mizushima)
      • Miracle Giants Domu-kun (漫画・アニメ, Manga and Anime, original by Shotaro Ishinomori) - Voiced by Ikuya Sawaki

8.1. Batting Statistics

• The bold numbers indicate the league leader for that season.

8.2. Fielding Statistics

• The bold numbers indicate the league leader for that season.
• Bolded years indicate a Diamond Glove Award win.

8.3. Managerial Record

• 1989-1996: 130-game season
• 2001-2004: 140-game season
• 2005: 146-game season

8.4. Uniform Numbers

• 27 (1969-1970)
• 8 (1971-1986, 2001-2005) - Retired by Hiroshima Toyo Carp.
• 88 (1989-1993)

8.5. Registered Name

• Koji Yamamoto (山本 浩司_{Yamamoto Kōji}^Japanese) (1969-1974)
• Koji Yamamoto (山本 浩二_{Yamamoto Kōji}^Japanese) (1975-present)