Jhin Runes explained
There's one set of runes for Jhin on patch
11.8
that is the clear favorite for LoL players and pros alike. The best Jhin Runes on the position 
Adc are Precision as the primary path and
Sorcery as the secondary path with a pick rate of 54%. Besides runes you should take a look on Jhin Build and if you are interested in pro matches take a look at Jhin Probuilds. If you want to discuss
Jhin then you should visit the champion subreddit.
Primary path on Jhin
Precision improves attack and sustained damage on Jhin troughout the match. Most of high elo players – and our LoL pros in the the major regions – have agreed that
Fleet Footwork is the best keystone rune to run on
Jhin. This keystone rune generates you a lot of sustain and increases your survivability against poke champions in lane. This is usually followed up by taking
Presence of Mind,
Legend: Bloodline and
Coup de Grace.
Presence of Mind helps Jhin with the mana problems by restoring missing mana, if a champion is killed.
Legend: Bloodline gives life steal, which aids in winning damage trades and fights in the later stages of the match. Jhin deals with
Coup de Grace more damage to targets with low health.
Secondary path on Jhin
When it comes to your secondary path, most
Jhin players prefer to go with
Sorcery.
Sorcery empoweres abilities of Jhin and increases the available champion resources. On the
Sorcery path, the best runes for Jhin are
Nimbus Cloak and
Celerity.
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,
Celerity boosts all movement speed bonuses to Jhin.