Out of the red, into the black

The Japanese are pretty superstitious. They don't like the number four, as in Japanese it sounds like the word for death, and I think six is unlucky too, though I have forgotten why. They also don't like their names written in red. I knew this, but I didn't know why until yesterday, when all I had to hand was a red pen to sign a receipt for a student. She told me that red ink was the colour that the wartime government used for conscription papers. If you got a "red letter" in the post it meant you were likely to be sent to your death in some far off jungle. I promptly found a black pen to fill out her receipt.