Last month, I withdrew some money — ¥100,000 to be precise — from an ATM near Tokyo's Shibuya Station.

I was on my way to a meeting and was in such a hurry that, while remembering to grab my bank card and receipt, I completely forgot to collect the cash from the machine — 10 crisp ¥10,000 notes.

It wasn't until I was paying for some pancakes after lunch that I realized my wallet was considerably lighter than it should have been and retraced my steps.