Beijing, Mar 25: China’s air force has held another round of drills in the disputed South China Sea and the Western Pacific after passing though Japan’s southern islands, the air force said on Sunday, calling such exercises the best preparation for war. China is in the midst of an ambitious military modernisation programme overseen by President Xi Jinping with a heavy focus on its air force and navy, from building stealth fighters to adding aircraft carriers. China insists it has no hostile intent, but its sabre-rattling in the busy South China Sea waterway, and around Taiwan, has touched a nerve in the region and in Washington.