The following is an annotated version of the fairy tale. I recommend reading the entire story before exploring the annotations, especially if you have not read the tale recently.
A LITTLE tailor was sitting cross-legged at his bench and was stitching away as busy as could be when a woman came up the street calling out: "Home-made jam, home-made jam!"
So the tailor called out to her: "Come here, my good woman, and give me a quarter of a pound."
And when she had poured it out for him he spread it on some bread and butter and laid it aside for his lunch. But, in the summer-time, the flies commenced to collect around the bread and jam.
When the tailor noticed this, he raised his leather strap and brought it down upon the crowd of flies and killed twelve of them straightway. He was mighty proud of that. So he made himself a shoulder-sash, on which he stitched the letters: A Dozen at One Blow.
When he looked down upon this he thought to himself: "A man who could do such things ought not to stay at home; he ought to go out to conquer the world."
So he put into his wallet the cream cheese that he had bought that day and a favourite blackbird that used to hop about his shop, and went out to seek his fortune.
He hadn't gone far when he met a giant, and went up to him and said: "Well, comrade, how goes it with you?"
"Comrade," sneered the giant, "a pretty comrade you would make for me."
"Look at this," said the tailor pointing to his sash.
And when the giant read, "A Dozen at a Blow," he thought to himself: "This little fellow is no fool of a fighter if what he says is true. But let's test him."
So the giant said to the tailor: "If what you've got there is true, we may well be comrades. But let's see if you can do what I can do."
And he bent down in the road and took up a large stone and pressed it with his hand till it all crushed up and water commenced to pour out from it.
"Can you do that?" said the giant.
The tailor also bent down in the road, but took out from his wallet the piece of cheese and pre tended to pick it up.
When he took it in his hand he pressed and pressed till the cream poured forth from it.
The giant said: "Well, you can do that fairly well. Let's see if you can throw."
He took another stone and threw it till it went right across the river by which they were standing.
So the little tailor took his blackbird in his hand and pretended to throw it, and of course when it felt itself in the air it flew away and disappeared.
The giant said: "That wasn't a bad throw. You may as well come home and stop with us giants, and we'll do great things together."
As they went along the giant said: "We want some twigs for our night fires. You may as well help me carry some home." And he pointed to a tree that had fallen by the wayside and said: "Help me carry that, will you?"
So the tailor said, "Why certainly," and went to the top of the tree, and said: "I'll carry these branches which are the heavier; you carry the trunk which has no branches."
And when the giant got the trunk on his shoulders the tailor seated himself on one of the branches and let the giant carry him along.
After a time the giant got tired and said: "Ho there, wait a minute, I'm going to drop the tree and rest awhile."
So the tailor jumped down and caught the tree around the branches again and said: "Well, you are easily tired."
At last they got to the giant's castle and there the giant spoke to his brothers and told them what a brave and powerful fellow this little tailor was. They spoke together and determined to get rid of him lest he might do them some harm. But they determined to kill him in the night because he was so strong and might kill twelve of them at a blow.
But the tailor saw them whispering together, and guessing that something was wrong went out into the yard and got a big bladder which he filled with blood and put it in the bed which the giants pointed out to him.
Then he crept under it, and during the night they brought their big clubs and hit the bed over and over again till the blood spurted out onto their faces.
Then they thought the tailor was dead and went back to sleep.
But in the morning there was the tailor as large as life. And they were so surprised to see him that they asked him if he had not felt anything during the night.
"Oh, I don't know, there seemed to be plenty of fleas in that bed," said the tailor. "I do not think I would care to sleep there again." And with that he took his leave of the giants and went on his way.
After a time he came to the King's court and fell asleep under a tree. And some of the courtiers passing by saw written upon his sash, "A Dozen at One Blow."
They went and told the King who said: "Why, he's just the man for us; he will be able to destroy the wild boar and the unicorn that are ravaging our kingdom. Bring him to us."
So they woke up the little tailor and brought him to the King, who said to him: "There is a wild boar ravaging our kingdom. You are so powerful that you will easily be able to capture it."
"What shall I get if I do?" asked the little tailor.
"Well, I have promised to give my daughter's hand and half the kingdom to the man who can do it, and other things."
"What other things?" said the little tailor.
"Oh, it will be time to learn that when you have caught the boar."
Then the little tailor went out to the wood where the boar was last seen, and when he came near him he ran away, and ran away, and ran away, till at last he ca to a little chapel in the wood into Which he ran, and the boar at his heels. He climbed up to a high window and got outside the chapel, and then rushed around to the door and closed and locked it.
Then he went back to the King and said to him:
"I have your wild boar for you in the chapel in the woods. Send some of your men to kill him, or do what you like with him."
"How did you manage to get him there?" said the King.
"Oh, I caught him by the bristles and threw him in there as I thought you wanted to have him safe and sound. What's the next thing I must do?"
"Well," said the King, "there's a unicorn in this country killing everyone that he meets. I do not want him slain; I want him caught and brought to me."
So the little tailor said, "Give me a rope and a hatchet and I will see what I can do."
So he went with the rope and hatchet to the wood, where the unicorn had been seen. And when he came towards it he dodged it, and he dodged it, till at last he dodged behind a big tree, till the unicorn, in trying to pierce, ran his horn into the tree where it stuck fast.
Then the little tailor came forth and tied the rope around the unicorn's neck, and dug out the horn with his hatchet, and dragged the unicorn to the King.
"What's the next thing?" said the little tailor.
"Well, there is only one thing more. There are two giants who are destroying everybody they meet. Get rid of them, and my daughter and the half of my kingdom shall be yours."
Then the little tailor went to seek the giants and found them sleeping under some trees in the woods. He filled his box with stones, climbed up a tree overlooking the giants, and when he had hidden himself in the branches he threw a stone at the chest of one of the giants who woke up and said to his brother giant, "What are you doing there?"
And the other giant woke up and said, "I have done nothing."
"Well, don't do it again," said the other giant, and laid down to sleep again.
Then the tailor threw a stone at the other giant and hit him a whack on the chin. That giant rose up and said to his fellow giant, "What do you do that for?"
"Do what?"
"Hit me on the chin."
"I didn't."
"You did."
"I didn't."
"You did."
"Well, take that for not doing it."
And with that the other giant hit him a rousing blow on the head. With that they commenced fighting and tore up the trees and hit one another till at last one of them was killed, and the other one was so badly injured that the tailor had no difficulty in killing him with his hatchet.
Then he went back to the King and said: "I have got rid of your giants for you; send your men and bury them in the forest. They tore up the trees and tried to kill me with them but I was too much for them. Now for the Princess."
Well, the King had nothing more to say, and gave him his daughter in marriage and half the kingdom to rule.
But shortly after they were married the Princess heard the tailor saying in his sleep: "Fix that but ton better; baste that side gore; don't drop your stitches like that."
And then she knew she had married a tailor. And she went to her father weeping bitterly and complained.
"Well, my dear," he said, "I promised, and he certainly showed himself a great hero. But I will try and get rid of him for you. To-night I will send into your bedroom a number of soldiers that shall slay him even if he can kill a dozen at a blow."
So that night the little tailor noticed there was something wrong and heard the soldiers moving about near the bedroom. So he pretended to fall asleep and called out in his sleep: "I have killed a dozen at a blow; I have slain two giants; I have caught a wild boar by his bristles, and captured a unicorn alive. Show me the man that I need fear."
And when the soldiers heard that they said to the Princess that the job was too much for them, and went away
And the Princess thought better of it, and was proud of her little hero, and they lived happily ever afterwards.
Jacobs, Joseph, ed. European Folk and Fairy Tales. New York: G. P Putnam's Sons, 1916.