A man crosses the border each morning on a donkey…

…and each day, his donkey is loaded with only bags of straw. When he reaches the bridge marking the border, the tax collectors search his bags to calculate what duty he must pay on his exports. Every day, they find nothing. And yet, in the evening, after their shift has finished and they are in the tea houses or restaurants in the city, they see the same man spending lots of money and boasting that he is in fact a smuggler and that no one can catch him.

Every day, incensed at his bold claims, the tax collectors obsessively search his bags of straw. They sift the straw, cut it into pieces, rip open the fabric of his bags, attempt to burn the straw, check his hat, his beard and even cut open his shoes in the hope of finding coins between the leather. And yet, each evening, he is seen back in the city growing ever more prosperous and ever more brazen, even offering to pay for the tax collectors meals and drinks while continuing to tell stories of his wily smuggling. The tax collectors continue their futile interrogations of the straw bags for years, to no avail.

This continues until, now a prosperous man, the smuggler moves away to another city and settles down to enjoy his wealth. Years pass and one day, in the market, one of the retired tax collectors meets his old foe and asks,

‘Mister, many years have passed: I am no longer a tax collector and we are just two old men. Please, you can tell me, what was it you were smuggling all that time?’

The smuggler replied, ‘Donkeys.’