Long ago in the mountains of Niigata Prefecture (or Echigo Province, as it was then called) lived a man known far and wide for his honesty. He farmed a meager patch in the mountains, growing black beans in poor soil, and just managed to eke out a living. One winter's night, on the second of January, the man had his first dream of the New Year, and this is what he dreamt.
In the dream God appeared to him and said, "Hey, you, you're always working in that field of yours, and yet at the end of the year you're no better off than at the start. Listen to what I'm saying to you: There's a chap that lives in the village the other side of the mountain. He's got a garden, and in that garden is a plum tree. You just take a shovel with you and dig around a bit under that tree and see if you don't find a pot of gold buried there."
The next day he set out for the village, cautiously excited and more than anything curious. It was getting dark when he arrived, but he found the house and knocked on the door. It was opened by the homeowner himself. "Excuse me, sir, but God told me in a dream about this house and the plum tree in the garden. He said that if I dug around under the tree I'd find a pot of gold. If that's true, we'll go halves. What do you say?"
The other replied, "It's late, too dark to be digging up the garden. Why not in the morning? You can stay the night here."
As soon as his guest was in bed, the man rushed out, grabbed the shovel, and began to dig. He dug and he dug, but for the life of him he could not find the pot of gold the visitor had dreamt was under the plum tree.
The next morning the man told his guest about his fruitless search. "Honestly, I would have shared any treasure I found," he assured him. "Once I thought we were in luck, for my shovel struck something hard. But it was nothing, though I could have sworn a kind of black mist rose out of the ground."
"Just goes to show that some dreams are only dreams," said the other. "Sorry for putting you out." And thanking his host for the hospitality, the man set out to return home.
On the trail he encountered a strange gentleman dressed in black. "Good day, sir. And where might you be headed?" he inquired. The stranger pointed in the direction of the man's home. "Well, as it will be dark soon and unsafe to continue your journey, please do me the honor of sharing my humble abode this evening." And so the two descended the mountain towards the man's village.
"Were you out for a walk?" the strange man at length inquired.
"No, it wasn't that," the other answered, proceeding to relate the tale of his dream and the pot of gold that wasn't. "But it's just as well, he concluded, I only know one thing in life, farming my small garden, and to be honest I not sure what I would have done if I'd found all that money."
At which the other smiled to himself.
Before long they reached the man's home. He fired up the hearth, set a pot of rice porridge to simmer, and busied himself making his guest comfortable.
The next morning the man in black was nowhere to be found. When our hero peered under the futon where the man had slept, imagine his surprise to find a gold jar stuffed to overflowing with pieces of gold. "It seems the jar I dreamt about turned into that mysterious man. And now my dream has come true," he mused.
With the money he purchased other plots, hired farmhands, and planted row upon row of black beans, which were highly prized. The honest farmer came to be known as "Black Bean Tycoon".
And this is the reason black beans are a New Year's tradition, expressing as they do the wish to be as healthy, wealthy, and hardworking as the hero of our tale.