Riven Runes explained
There's one set of runes for Riven on patch 14.20 that is the clear favorite for LoL players and pros alike. The best Riven rune paths on the position 
Top are 
Precision as the primary path and 
Sorcery as the secondary path with a pick rate of 62%. Besides picking runes on Riven you should learn how to play Riven and if you are interested in pro matches take a look on how a pro builds Riven. If you want to discuss 
Riven then you should visit the champion subreddit.
Riven runes from primary path
Precision improves attack and sustained damage on Riven troughout the match. Most of high elo players – and our LoL pros in the the major regions – have agreed that 
Conqueror is the best keystone rune to run on Riven. This keystone rune provides additional power in the later stages of a game. As soon as Conqueror is fully charged, Riven deals additional damage and gains life steal. Other primary runes on Riven are 
Triumph, 
Legend: Alacrity and 
Last Stand.
Triumph restores on Riven a part of missing health and award bonus gold, if a champion is killed. Legend: Alacrity grants additional attack speed to Riven. With Last Stand you deal more damage while you are at low health.
Riven runes from secondary path
When it comes to your secondary path, most Riven players prefer to go with Sorcery. Sorcery empoweres abilities of Riven and increases the available champion resources. On the Sorcery path, the best runes for Riven are 
Transcendence and 
Nimbus Cloak.
Transcendence for some more Ability Haste. Nimbus Cloak, which grants movement speed upon using a summoner spell, works amazingly well with junglers in particular as they take the shortest cooldown summoner spell, 
Smite.
FAQ for Riven Runes
Which is the best keystone rune on Riven?
The best keystone rune on Riven is Conqueror. This Riven runes setup is then referred as Riven Conqueror.
What runes does Riven use?
Runes from the paths Precision and Sorcery are the most used runes on Riven. For the exact pick rates of Riven runes used, you have to study the rune distribution presented.