Dome Advantages
Approximately half of NPB's 12 teams play in dome stadiums. Tokyo Dome (Yomiuri), Kyocera Dome Osaka (Orix), Belluna Dome (Seibu), Vantelin Dome Nagoya (Chunichi), and Mizuho PayPay Dome Fukuoka (SoftBank) are the representative dome venues. The primary advantage of dome stadiums is weather independence, with no rain cancellations and stable game scheduling. NPB features 143 regular-season games plus the Climax Series and Japan Series, and rain cancellations during this packed schedule lead to doubleheaders and games on travel days, increasing player burden. Dome stadiums fundamentally eliminate this problem. Climate control avoids the intense summer heat and humid rainy season, providing comfortable viewing conditions. PayPay Dome in Fukuoka notably features a retractable roof, allowing flexible operation based on weather conditions. From a business perspective, the elimination of rain-cancellation revenue loss contributes to franchise stability. Ticket sales, food and beverage, and merchandise revenue unaffected by weather make annual revenue forecasting easier. Dome construction costs range from 50 to 100 billion yen, with annual maintenance reaching 20 to 30 billion yen. Outdoor stadiums cost 10 to 30 billion yen to build, giving them a cost advantage. However, considering that lost revenue per cancelled game ranges from tens of millions to 100 million yen, long-term return on dome investment is quite feasible. Additionally, dome stadiums can host concerts, exhibitions, and other non-baseball events, with high year-round utilization rates serving as a business strength. Tokyo Dome operates over 300 days annually, hosting concerts and martial arts events in addition to approximately 50 baseball game days.
Outdoor Appeal
Outdoor stadiums offer their own unique appeal. Koshien Stadium (Hanshin), MAZDA Zoom-Zoom Stadium Hiroshima (Hiroshima), ZOZO Marine Stadium (Lotte), Rakuten Mobile Park Miyagi (Rakuten), Meiji Jingu Stadium (Yakult), and Yokohama Stadium (DeNA) are the representative outdoor venues. At outdoor stadiums, wind and temperature directly affect games, which is part of baseball's charm. At Koshien Stadium, the "Hamakaze" blowing in from Osaka Bay pushes back balls hit toward right field, suppressing right-handed hitters' home runs. This wind is an ally for Hanshin pitchers and a threat to opposing right-handed batters. ZOZO Marine Stadium, located along the coast, is known as a "magic ballpark" where strong winds make fly ball trajectories unpredictable. Days with wind speeds exceeding 10 meters per second are not uncommon, and outfielder defensive ability can determine game outcomes. The sense of openness from watching baseball under open skies is an experience unavailable in dome stadiums. Watching a night game as the sky changes color at dusk, enjoying a beer while feeling the summer evening breeze, experiencing the Climax Series in the crisp autumn air - enjoying baseball alongside the changing seasons is a charm unique to outdoor venues. MAZDA Zoom-Zoom Stadium Hiroshima, opened in 2009, features an open design where the cityscape is visible from the concourse, pioneering the "ballpark-type" outdoor stadium concept. Offering diverse viewing styles including sand-covered seats and barbecue terraces, it significantly contributed to increased Hiroshima Carp attendance. ES CON FIELD HOKKAIDO, with its retractable roof and natural grass, offers a "best of both worlds" design that can switch between outdoor and indoor modes based on weather, serving as a model case for future stadium construction.
Ballpark Game Impact
Stadium structure directly affects game outcomes. Tokyo Dome is known as a "homer-friendly ballpark" - while its dimensions of 100 meters down the lines and 122 meters to center field are standard for NPB, the air conditioning currents are said to extend batted ball distance. In fact, the average number of home runs per game at Tokyo Dome tends to exceed other venues, to the point where the nickname "Tokyo Domerun" was coined. Conversely, Koshien Stadium's Hamakaze suppresses right-handed hitters' home runs, making it a left-hander-friendly park. Vantelin Dome Nagoya is known as a pitcher-friendly park with high fences, and the Chunichi Dragons' traditional emphasis on pitching in their roster construction reflects this stadium characteristic. Stadium characteristics influence team roster construction, with teams based in homer-friendly parks tending to emphasize power hitters. The Yomiuri's aggressive acquisition of power-hitting foreign players has been part of a strategy to leverage Tokyo Dome's characteristics. Meanwhile, teams based in spacious parks emphasize pitching and defense, pursuing baseball that leverages speed. The Lotte Marines, based at ZOZO Marine Stadium, have built their team around speed-based offense and solid defense as countermeasures against strong winds. In recent years, the spread of sabermetrics has made park-factor-adjusted player evaluation commonplace, with metrics that remove stadium influence to measure "true ability" gaining importance.
Ballpark Future
NPB stadiums will continue evolving. ES CON FIELD HOKKAIDO's success has established "ballpark-type" stadiums as NPB's trend. Stadiums functioning as integrated complexes combining game viewing with dining, shopping, and leisure extend visitor stay times and increase per-person spending. Aging stadium replacements and renovations continue, with improving fan viewing experience becoming a critical priority for each team. Meiji Jingu Stadium, approaching 100 years since its 1926 opening, has replacement plans underway. The new stadium targets completion around 2028 as part of a large-scale redevelopment project involving a site swap with Chichibunomiya Rugby Stadium. Yokohama Stadium has undergone phased renovations including seating expansion and concourse enlargement. There is no definitive answer to whether dome or outdoor stadiums are superior - each stadium's personality and appeal generate NPB's diversity. Some fans seek weather-independent comfort while others want to enjoy baseball in nature. What matters is that each stadium maximizes its characteristics to provide fans with a one-of-a-kind viewing experience. Stadiums are not merely game venues but NPB culture itself, and their evolution shapes NPB's future. Going forward, sustainability considerations including reduced environmental impact and renewable energy utilization are expected to be incorporated into stadium design.