Amumu Runes explained
There's one set of runes for Amumu on patch 15.12 that is the clear favorite for LoL players and pros alike. The best Amumu rune paths on the position 
Support are 
Inspiration as the primary path and 
Resolve as the secondary path with a pick rate of 77%. Besides picking runes on Amumu you should learn how to play Amumu and if you are interested in pro matches take a look on how a pro builds Amumu. If you want to discuss 
Amumu then you should visit the champion subreddit.
Amumu runes from primary path
Inspiration opens creative opportunities on Amumu troughout the match. Most of high elo players – and our LoL pros in the the major regions – have agreed that 
Glacial Augment is the best keystone rune to run on Amumu. This keystone rune slows enemy champion on your first basic attack. This slow can by followed up by a skill shot of Amumu to force the opponent in a dangerous situation. Other primary runes on Amumu are 
Hextech Flashtraption, 
Biscuit Delivery and 
Cosmic Insight.
Having an extra way to decrease the distance with the Hextech Flashtraption will make an engage much easier to pull off. Biscuit Delivery is a great rune for laning as it gives additional health and mana, which can help in more aggressive lanes. Cosmic Insight grants summoner spell and item haste.
Amumu runes from secondary path
When it comes to your secondary path, most Amumu players prefer to go with Resolve. Resolve empowers the survivability of Amumu and increases the tankiness. On the Resolve path, the best runes for Amumu are 
Revitalize and 
Bone Plating.
Revitalize inceases heals and shields you distribute or receive. Bone Plating make Amumu overall tankier, by decreasing the amount of poke damage in the early game.
FAQ for Amumu Runes
Which is the best keystone rune on Amumu?
The best keystone rune on Amumu is Glacial Augment. This Amumu runes setup is then referred as Amumu Glacial Augment.
What runes does Amumu use?
Runes from the paths Inspiration and Resolve are the most used runes on Amumu. For the exact pick rates of Amumu runes used, you have to study the rune distribution presented.