TMTPOST -- The yen weakened across the board on Tuesday, while the U.S. dollar remained steady, after U.S. President Donald Trump announced a fresh round of 25% tariffs on imports from Japan and South Korea, marking the latest twist in his unpredictable trade war. Trump on Monday began notifying U.S. trade partners, including major exporters Japan and South Korea, that the new tariffs would take effect on August 1. However, he signaled flexibility, saying he was open to delaying implementation if countries came forward with alternative proposals.