Welcome to Warhammer. Sound the trumpets and beat loud the drums of war, for the weighty tome you hold in your hands is your key to entering a dark and bloody land. It is a world of Daemons and sorcery, a brutal era of warfare and conquest. Warhammer, the game of fantasy battles, brings all the action onto your tabletop. You command armies of miniatures in a game that promises bold manoeuvre, daring riposte and untold slaughter.  The game of Warhammer makes you the general of an army of fantasy miniatures. Regiments of resplendent High Elves, the ragged hordes of ravenous ratmen known as Skaven, the Undead legions of the Vampire Counts or any of the other dozen army types, march, manoeuvre and charge into the fray on your orders. At your command, hails of arrows and eldritch bolts of magic are unleashed upon the foe. But it is in the brutal close quarters of combat that most battles must be won, by stalwart troops and legendary heroes.

Post 1.2 hotfixes, and added shooting in rear and front

Warhammer - The Game of Fantasy Battles - 9th Edition v.2.1

Main Rulebook

A close combat attack is any attack that is performed against units in base contact during the close combat phase, including Stomps and Impact Hits and other attacks that normally hit automatically.

What is a Close Combat Attack?

Unlike other phases of the game, the combat phase offers both sides a chance to inflict damage on the foe, although you, as the player whose turn it is, will be the one choosing the order of the combats. All close combats must be resolved during this phase – a unit in combat cannot choose not to fight, for whatever reason. After all, once your warriors have charged into the enemy, they are not going to simply sit down and amicably discuss their differences! Most combats involve a single unit fighting a single opposing unit, so that's what we'll discuss first. Sometimes however, you'll end up with a multiple close combat where there is more than one unit fighting on one or both sides. Multiple close combats have some additional rules, which you'll find discussed towards the end of the chapter. As all the rules for a normal close combat also apply to a multiple close combat, you'll probably find it easier (and clearer) if you just work your way through the section. 