of the outfield, two new sections were constructed, while grass seating was maintained on either side of the new scoreboard. Beyond the left field seating, an 8 metre (26 ft) high mound dubbed "Rakuten Mountain" was created using leftover dirt excavated during construction. The sloped hill connected the area behind the stadium to the grass seating area in left field. Around the front of the stadium, a large, concrete frame was constructed that expanded the concourses, allowing for restrooms and shops to be upgraded and added. In addition to stadium infrastructure, baseball facilities and amenities were also modified. The baseball field's outfield wings were extended from , the largest in NPB at the time, and it's natural turf was replaced with artificial FieldTurf. A facility housing the pitchers' bullpens was added on the outside of the stadium along its third base side, allowing fans to watch players warm up. Construction concluded on March 20 and the Eagles held their first game at the stadium on April 1, 2005. Work on the second phase of the project started the following offseason in October 2005. The concrete frame constructed around the front of the stadium during the first phase was expanded upon and completed, resulting in a five-story structure that contained a food court, box seats, the TV and radio booth, the press box, and a premium lounge. Additional infield seating was added via a new section erected atop the building that houses the bullpens on the third base side and box seats and an enclosed lounge with a video screen above it built along the first base side. Four other adjoining buildings were built adjacent to the stadium on the first base side. These facilities housed the team's offices and clubhouse, two indoor practice areas, and a parking garage. With phase two concluded, Rakuten had spent ¥7 billion in total on the two-year modernization project. Implementation of the "ball park concept" (2006–2018) Prior to the 2007 season, the first ribbon display at a baseball stadium in Japan was added to Miyagi Stadium's backstop. Two more ribbons were added the following season to the outfield seating areas and the right field lawn section was converted to a group seating area that provided tables for groups up to five people. Upgrades continued in 2009 and 2010 when the sunken backstop seats were enclosed to help create the new "Prestige" section, and the large