TIW
God of War
"victory runes learn
if thou seekest to win
On thy sword hilt scratch
some in the channel
and some on the flat,
and twice call on TIWAZ"
Tuesday is named for the god Tiw, also known as Tyr, or Tiu, by the Anglo-Saxons, replacing the Roman god Mars when the Anglo-Saxons changed their week-day names to reflect their own gods.
Tiw was once regarded as the All-father of the Nordic gods until he lost his rank to Odin. Warriors worshiped him for he is said to grant victory and protection in times of battle, they would also carve Tiw's rune (tiwaz, the upright arrow) on their swords.
Tiw was also know as the one handed God, the reason for this is explained in the following legend:
Loki, a god renowned for causing chaos where ever he went, had many unusual children, the most terrible of these, was the giant wolf Fenrir. At first the gods loved Fenrir, and he grew up happily in Asgard, but it became so huge and fierce that the gods soon became nervous of him, and eventually only Tiw was brave enough to feed him. It was said that when the wolf opened its mouth, its jaws stretched from sky to earth.
The gods relised that they would have to find a way to control Fenrir before he grew even larger and out of control. They decided that the best way would be to chain him, but it would take a very special chain to be able to hold such a beast. They asked the dwarves to make a magic chain, made of secret things like the noise of a moving cat, the roots of a mountain and the breath of a fish. When it was finished, the chain looked like a cord made of silk, but nothing could break it.
When they approached Fenrir with the chain he was suspicious, and wouldn't allow anyone to come near him with it. The gods had to trick the wolf into letting itself be chained by saying it was a test of his strength. Fenrir was suspicious and agreed to be chained but only if Tiw, the only god it trusted, agreed to put his hand in the wolf's mouth as a pledge of faith. The gods quickly tied the wolf up. Fenrir struggled against his bonds, then relising he had been tricked, snapped his jaws closed in anger, and Tiw's hand was bitten clean off. Tiw lost his hand, but at least the gods were now safe from the wolf.

It was Tiws right hand that he placed in the wolfs mouth, leading to much debate about his left-handedness.
In the Norse culture the right hand was given for a pledge, which could be why it was the right hand that was placed in the wolf's mouth. It has also been noted, however, that the offering of the right hand is to show that it is free of weapons. A left-handed person was sometimes considered evil because he could use a weapon with his left hand even though he shook with his right hand.
Tiw was a warrior god, loosing his right hand to the wolf was an amazing sacrifice for him to make.