Can recommend either COH and/or COMBAT COMMANDER games--although CONFLICT OF HEROES comes in a big box and may be harder to handcarry on a plane and/or costly to mail back home! Rules are more involved in COH and moreso in COMBAT COMMANDER, but they aren't hard. Chaos level is high in both games if you like that.
Welcome to the Social Website! You definitely have been playing some really good games! For tactical games, I'd recommend WHITE STAR RISING by Lock 'N Load--it's on sale through Black Friday weekend. Good tactical game if you are new to wargaming. Shipping to Japan is way expensive, but the 25% discount on the game should help!