Joh-hi was big. He was strong. He was the fastest runner of the Sri-hi horse tribes. He had passed the trial of virility, siring children on ten maidens of the village having lain with each of them a single night only. By Sri-hi standards he was everything a young man could ever hope to be.

Indeed, Joh-hi meant literally stallion, the highest term of praise a man could earn, and all the village agreed (though some with envy and some with genuine dislike) that Joh-hi warranted the title, for he was the very image of the plains stallions they so revered. His hair was long and black and glossy; his skin was dark and shone so that he appeared like the great blood-dark bays that pawed the earth and whinnied their challenge to the plains winds. Muscles rippled beneath his skin, and the soles of his bare feet, which had never known boot or sandal, were hard as any hoof.

Now it happened that every hundred years would pass the Year of the Horse, when a young man would be Chosen from all the Sri-hi tribes and sent to the Old Mare of the Rock, an ancient woman older by far than any living thing has a right to be, and equally blessed with wisdom. She was skilled in magic, and it was she that spoke on the Sri-hi's behalf when the gods needed appeasing or some miraculous boon needed asking.

On the longest day of the Year of the Horse, the Chosen one would approach the Old Mare of the Rock and beseech her to grant him the ultimate honour of the Sri-hi way - to be transformed into a glorious stallion, so that his intelligence and strength and virility and bravery (etcetera - it was a long list) would thus be passed onto the herds and incur the blessings of the gods.

Some Chosen were stoic in this matter, accepting it as the will of the gods. Some truly believed it was a great honour. And some said, "Bugger this for a game of Tra-shi!" and had to be clubbed insensible and carried to the Old Mare (where she would usually listen impassively to claims that "he was overcome by the great honour".)

It was no surprise at all when Joh-hi was Chosen, and it was noted that his chest swelled with pride and his eyes seemed positively to glow. Here, the people whispered, was truly a stallion in human form, and it would be only just for his outer form to match his inner. And then perhaps they wouldn't have to listen to him bragging about his own prowess (a good stallion trait but never a popular human one) and he could prove his virility with the willing herd mares who did not expect an expensive dowry. And not a few secretly hoped that arrogant Joh-hi might perhaps trip as he ascended the stone steps to the Old Mare's throne and fall base over apex.

Alas for those doom-wishers, Joh-hi ascended the steps with the prancing confidence of an experienced stallion courting a favourite paramour, head held high and feet never faltering.

"Old Mare!" he announced, and his voice was strident as a stallion's challenge. "I have been Chosen on this Year of the Horse! I call upon you to transform me here and now before all, so that I may take my place amongst the herds and pass on my seed to the Sri-hi bloodlines!"

The Old Mare stood and regarded Joh-hi through narrowed eyes for long seconds, while all below waited in awe. Whatever one's opinion of Joh-hi, it wasn't every day one witnessed magic of this calibre.

"Transformation is not an easy magic," she said at length. "Have you the bravery for this transition? There is much pain and discomfort. I have my doubts that you can withstand this."

"I am the bravest here," boasted Joh-hi. "I am not afraid."

"Really?" she asked. "I think that fully half the people before us are braver than you."

Joh-hi looked startled and then angry. "I will meet any test you can deal out!" he asserted. "I am the bravest man here!"

"That I doubt not," she said. "But I will test you. I will inflict upon you one tenth part of the pain and discomfort you must endure. Fully half the people before you take this test and pass it. We will see if you have the courage."

But Joh-hi knew he was the bravest of all men, and truly worthy to be a stallion, and so he said, "Test me, Old Mare. Nothing you can do will shake my purpose."

"Very well then. Steal yourself, for nothing any man has ever experienced can prepare you for this," she warned. She raised her gnarled hands to the sky and called upon lightning and wind.

The people shielded their eyes and winced, unable to see Joh-hi's body as the lightning blinded them and the wind whipped dust into their eyes, but they heard his screams, strangely high-pitched. And then it was done, and they stared upon the Old Mare's miraculous work, for Joh-hi was transformed beyond recognition.

Joh-hi looked down at himself in horror. His body was grossly swollen. He was numb in his hand and feet, and his spine was a cruel agony like nothing he had ever known. His bladder ached as if he had stood herd-watch without relief for eight hours, and his stomach crawled with nausea. All his body seemed one huge discomfort and his grace and strength had become an all-consuming weariness. He felt awkward and clumsy. "What have you done to me?" he demanded, and again his voice was much shriller than he was accustomed to. He flushed in humiliation. "What is this unspeakable torment?"

"This is the test," the Old Mare announced. "And what you feel now is as nothing for it shall grow worse, and yet this test is only a fraction of what you must endure if you wish to become a stallion. Survive this for four moons and you shall indeed stand proven as the bravest man who ever lived. I have made you into a woman five months pregnant."