Director Kazuya Shiraishi delivers more of a yakuza movie homage than a revamp in “The Blood of Wolves,” a cop thriller based on Yuko Yuzuki’s novel of the same Japanese title. But the film’s real inspiration, as Shiraishi himself has admitted, is “Battles Without Honor and Humanity,” a seminal 1973-74 five-part series directed by Kinji Fukasaku. Tracing a true-life 20-year gang war in Hiroshima and nearby Kure, “Battles” had a contemporary feel and a shot-on-the-fly propulsion. “The Blood of Wolves” is also set in Hiroshima but its story of a veteran cop (Koji Yakusho) suspected of being in cahoots with the yakuza unfolds in 1988 and has the air of a last hurrah, with its dirty hero being the last of his species.