Fleet Footwork is going to give you a lot more sustain than Unsealed Spellbook. The only way you can make up for the bonus sustain is by teleporting back to lane; that makes you lose your heal for a while, and at best it's equitably good. If you'd rather take Lethal Tempo for the huge attack speed buff, you can do that too, but I think the sustain and bonus damage from either keystone is better than getting a few free teleports in, especially since you lose the survivability of heal.

Stopwatch and footwear are both solid substitutes; I find that I can get in plenty of farm, and the extra 5% cdr on my W for dealing aoe damage is nice. However, stopwatch is quite good; I get away without it because of spellshield. Still, viable swap. In case you're worried about gold, 5%cdr is worth about 130 gp. It has the bonus of you can't buy that increase in max cdr, which I think makes it even out.


While you could use RFC, you don't really do that much damage in a single hit. So, I prefer to not bother; static shyvv might be a better replacement if you're looking for a similar item profile.

Largely, I'm of the opinion that there are lots of builds and rune pages, some of which are more viable than others. I would disagree with taking unsealed as your keystone, but other swaps to build and runes will largely depend on your playstyle, which is why I prefer to concentrate on gameplay in my guides.

Well, I'd like to note that it can really go either way. However ...

Thunderlord's is going to improve your mid-length trades a lot. In a single hit, if you've been stacking up Fervor, it's true that you'll deal a bit more damage. However, for a trade that lasts a little longer, you can add a Boomerang Blade to the mix. So, if you activate BB for movespeed, go in, AA, and have BB hit on the way back out, you'll proc thunderlord's. This is a pretty standard move for me, and it really helps slam your opponent's health down in laning phase. More so if I bothered to max BB, but it's whatever. The other place that FoB could shine is in extended trades, where you're just "sitting" there trying to kill the enemy first. In basically all of these trades' Sivir is going to die, and they should be avoided. Almost all ADC's deal more single target damage than Siv.

If you were choosing it for waveclear, FoB is not going to help that much since Sivir can destroy a wave quickly either way.

In a teamfight, FoB is going to be stronger than Thunderlord's, as it will help all of your Ricochet attacks deal more. In reality, even at max stacks this is only going to be 5-6 extra damage, but a crit build would bring it up to 14 per hit on the bounces (due to scaling). However, whatever target you have chosen to focus on is going to be taking a lot of damage due to thunderlord's (level 18 full build with about 400 AD is going to be 300 damage), which is more than FoB will give. However, if you were hitting the entire team, it would take about 4 hits to put FoB as a higher damage mastery, but this takes two casts of Ricochet, which would take even longer. Furthermore, thunderlord's deals magic damage, and chances are you'll be attacking a tank with high armor, so even more piercing there.

All this math was assuming, of course, you were at max FoB stacks. FoB takes a while to stack up as a ranged unit, so really you'll be dealing a bit less damage than my numbers suggest.

In summary, if you're going to be doing a lot of extended teamfighting and one-hit poking in lane, FoB will indeed be a superior mastery. If you are going to be doing a slightly longer engagement in lane, fighting against a lot of small groups, or fighting short teamfights, you'll want Thunderlord's. My style leans thunderlord's, but your style could of course be different.

Sorry that took so long, but I wanted to be thorough. I hope you found it helpful!

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