TOKYO (Reuters) – Japan’s promised economic stimulus must be big enough to exceed the economy’s output gap of about 15 trillion yen ($100 billion), a senior ruling party official said on Sunday. “The gap in Japan’s gross domestic product (GDP) is now around 15 trillion yen. It’s not enough to just fill this gap,” said Yoshitaka Shindo, executive acting chairperson of the ruling Liberal Democratic Party’s (LDP) policy research council. “Both quality and size is important,” Shindo said of the package, being crafted by Prime Minister Fumio Kishida’s administration to cushion the blow from rising …