The Hiroshima Carp continued their perfect start to the new season Tuesday in the Central League with a 3-2 walk-off win over the winless Hanshin Tigers. Ryoma Nishikawa’s bases-loaded, two-run single in the ninth inning at Mazda Stadium left the Carp with four wins from four games. The Yomiuri Giants beat the Yakult Swallows 5-3, while the DeNA BayStars won 4-0 against the Chunichi Dragons after Fernando Romero (1-0) threw eight shutout innings. In the Pacific League, the SoftBank Hawks are the only team to win all four games after edging the Lotte Marines 2-1 after 10 innings, scoring the go…