SINGAPORE — On 26 March 1941, Japanese Foreign Minister Yosuke Matsuoka arrived in Berlin for a visit to meet Nazi Germany’s dictator Adolf Hitler and his German counterpart Joachim von Ribbentrop with the aim of deepening relations between their two countries. One city emerged as a key subject of their talks amid the ongoing World War II (WWII): Singapore. At the time of Matsuoka’s four-day visit to the German capital, Singapore was about eight months away from experiencing its first bombing of WWII. To Hitler and other top Nazis, if the strategically crucial British colony were to fall to the...