
Reviewed for patch 7.3b

Favorable matchup
Reviewed for patch 7.3b
Jhin has no dashes and relies on four shots. When your support locks him down, Daredevil Impulse carries you to him, Wild Rush stays free to follow up, and Whisper's reload gives you time to reach Inferno Trigger.
According to Riot, your attacks against immobilized enemies dash you into attack range. Jhin has no leaps or charges to get out: if your support locks him down, you arrive without spending Wild Rush. Mind the fourth shot: in 7.3b its standard crit damage rises from 80% to 85% and the missing-health damage caps at level 10 instead of 15.
After the fourth shot, Jhin has to reload before firing basic attacks again. That is when you empty the combo: alternate Flair, basic attacks and Blade Whirl, and each different hit pushes Daredevil Impulse toward the S rank Inferno Trigger requires.
Blade Whirl damages around you and counts as a distinct hit for Daredevil Impulse: use it to reach S sooner, not as a defense against his shots. Curtain Call stops on the first champion and slows hard: if Jhin channels from afar, don't cross toward him in a straight line.
Go in when your support immobilizes Jhin or when he misses Deadly Flourish. Without allied crowd control and with his root available, stay out of range and let him spend shots on the wave.
If you play Jhin, the danger comes with the enemy support's crowd control: every immobilize brings Samira in without spending Wild Rush. Stay outside that range, root her with Deadly Flourish when she comes in after a hit from your support, and save the fourth shot for when she is close to S.

Favorable matchup
Reviewed for patch 7.3b
Lucian turns every Jhin reload into a trade: dash in with Relentless Pursuit, land the Lightslinger double shot and leave before he has bullets again. The same dash lets him step out of Deadly Flourish.
Jhin fires at a fixed cadence and relies on four shots. Lightslinger makes your next basic attack after an ability fire twice and Piercing Light pierces through the wave: you pack your damage into the seconds when Jhin can't answer with basic attacks.
Deadly Flourish is a very long-range shot that passes through minions, stops on the first champion and roots if you were hit recently. Relentless Pursuit takes you off its line, and Lightslinger attacks lower its cooldown: trading well gives you the dodge back sooner.
Trade as soon as Jhin fires his fourth shot or spends Deadly Flourish. If he has bullets and the root available, punish with Piercing Light through the wave and stay out.
As Jhin, the challenge is not handing over the reload: don't fire the fourth shot if Lucian can dash in right after, and reload behind your minions. Place Captive Audience on his dash path and throw Deadly Flourish once he has used Relentless Pursuit.

Execution matters
Reviewed for patch 7.3b
Sivir contests the lane with Jhin without stepping on his traps: Boomerang Blade and Ricochet clear the wave from range, Spell Shield blocks Dancing Grenade, which Jhin launches at an enemy, and On The Hunt speeds up your team.
Riot describes Spell Shield as blocking an enemy ability cast on Sivir, and Dancing Grenade is a cartridge Jhin launches at an enemy. If you block it, you restore health and gain Fleet of Foot's speed. Deadly Flourish is a line shot: dodge it by moving, don't count on the shield.
Boomerang Blade damages everything it crosses on the way out and back, and Ricochet makes your basic attacks bounce. You clear the wave without walking over the invisible Lotus Traps from Captive Audience and keep control of the lane.
On The Hunt gives nearby allies speed and lowers your basic ability cooldowns, Spell Shield included. Jhin has no dashes: use it to reach him after the fourth shot or to get your team out of Curtain Call's range.
Fight once Jhin has spent Deadly Flourish or you've dodged it. If he still has it, back off: your minions don't cover you, because the root passes through them.
Against Sivir, don't throw Dancing Grenade while her shield is available. Her pressure comes from the wave, not from engage: poke with the fourth shot, use Deadly Flourish after a hit from your support and don't stand where Boomerang Blade hits you both ways.