At Bletchley Park, diplomatic messages from Tokyo to the embassy in London are intercepted, warning them to expect a message, disguised as a weather forecast, indicating the outbreak of hostilities with the UK, the US, or the USSR. If it’s with the US, it will read higashi no kaze, ame (east wind, rain); if it’s with the USSR, kita no kaze, kumori (north wind, cloudy); if it’s with the UK, nisha no kaze, hare (west wind, fine weather). Upon receipt, all code books must be burned. The message for the UK and the US will arrive late on Sunday evening, December 7th, without specifying exactly where.
