An american in japan

An American went to Japan. He had a Japanese servant who was
very polite. The American wanted to get up very early one morning
and said to the servant:
"Wake me up at six o'clock, please. Don't forget to do it. I have
very important business in the morning."
At six o'clock, the servant entered the American's room very
quietly and, seeing that the American was fast asleep, took a sheet
of paper and wrote some words on it. Then he left the room as
quietly as he had entered it.
The American woke up at eleven o'clock, jumped out of bed,
looked at his watch with horror and saw the sheet of paper on the
table. He read these words on it: "Dear sir, it is now six o'clock.
Please get up at once."