Cho'Gath Runes explained
There's one set of runes for Cho'Gath on patch 13.24 that is the clear favorite for LoL players and pros alike. The best Cho'Gath rune paths on the position 
Top are 
Resolve as the primary path and Inspiration as the secondary path with a pick rate of 55%. Besides picking runes on Cho'Gath you should learn how to play Cho'Gath and if you are interested in pro matches take a look on how a pro builds Cho'Gath. If you want to discuss 
Cho'Gath then you should visit the champion subreddit.
Cho'Gath runes from primary path
Resolve empowers the survivability of Cho'Gath and increases the tankiness. Most of high elo players – and our LoL pros in the the major regions – have agreed that Grasp of the Undying is the best keystone rune to run on Cho'Gath. This keystone rune gives Cho'Gath alot of sustain and helps to force your opposing champion out of the lane. Other primary runes on Cho'Gath are Demolish, Second Wind and Overgrowth.
Demolish increases your pressure on the enemy turrets. This rune will help you to punish bad roams or backtimings of your lane opponent. Second Wind powers up your sustainablity in lane by healing after taking damage from an enemy champion. Overgrowth increases your maximum amount of health.
Cho'Gath runes from secondary path
When it comes to your secondary path, most Cho'Gath players prefer to go with Inspiration. Inspiration opens creative opportunities on Cho'Gath troughout the match. On the Inspiration path, the best runes for Chogath are Cosmic Insight and Magical Footwear.
Cosmic Insight grants summoner spell and item haste. Magical Footwear allows Cho'Gath to focus on those essential core items without the need to spend the additional 300 gold on boots.
FAQ for Cho'Gath Runes
Which is the best keystone rune on Cho'Gath?
The best keystone rune on Cho'Gath is Grasp of the Undying. This Cho'Gath runes setup is then referred as Cho'Gath Grasp of the Undying.
What runes does Cho'Gath use?
Runes from the paths Resolve and Inspiration are the most used runes on Cho'Gath. For the exact pick rates of Cho'Gath runes used, you have to study the rune distribution presented.