06 Sep 2014 08 Sep 2014
Start a new tutorial world, Press B to skip the tutorial on how to play and then run over to these coordinates;
There will be a chest with a Iron sword with Smite V enchantment which increases damage to "undead" mobs (skeletons, zombies and zombie pigmen).
Now simply wait until night and kill a zombie or skeleton with the Smite V sword!
Extra: If your lazy like me and cant wait until night to get the achievement, there is a dungeon with a zombie spawner at these coordinates;