Kai'Sa is very vulnerable to getting outranged by mages and long range carries.
Make sure to place wards in your blind spots so you can see Kai'Sa coming.
Kai'Sa is very good at picking off isolated enemies. Stick together against her.
The stat comparisons shown on this page show several significant Yuumi against Kai'Sa matchup stats that can help you interpret the distinctions between the two. For instance, Yuumi’s KDA ratio ([kills + assists] / deaths) of NaN is more than Kai'Sa’s ratio of NaN, highlighting that Yuumi may be more central to her team's team fighting potential than Kai'Sa. This observation is largely caused by the differences in assists.
Yuumi often has a significantly smaller longest killing spree than her counter does. On average, she receives less damage than Kai'Sa. This often reflects different amounts of tankyness; however, it can also indicate that the champion with increased health has less agility and thus is not able to kite away from additional harm when poked or engaged.
Both League of Legends champs are great champions. Both have their strengths, weaknesses, and counters. In the game's current meta, Yuumi usually loses when trying to fight Kai'Sa, with a 46.4% win rate. As a result, Yuumi makes a bad counter to Kai'Sa.
While Yuumi does have a lower winrate than Kai'Sa, when facing one another, Yuumi also has a much lower difficulty level that makes her a less time consuming champion to learn and master. You should expect to face a difficult match when picking Yuumi into Kai'Sa.
Moreover, Yuumi also has a great amount of CC and other utility, a similar amount to Kai'Sa. This often makes her just as valuable during teamfights, especially when fighting champions with a lot of burst damage.
While there isn't a single best champion overall in League of Legends, in Yuumi vs Kai'Sa matchups, Kai'Sa is the better champ with a much lower win rate, less champion complexity, and a similar amount of utility to help out your teammates during teamfights.
Yuumi is a bad counter for Kai'Sa. You will do well by focussing your strategy on maximizing your CS and clearing objectives. If you can do that, you should be able to stand on your own as Yuumi against Kai'Sa.
If you would like to truly master Yuumi in order to counter Kai'Sa during both the early game and mid / late game phases of League of Legends, you should keep reading to learn a few extra tips and tricks for this matchup. If you pay attention to the build and tips shown here, you will increase your win rate significantly and be closer to League of Legends pro players.
Yuumi most often accumulates a lot less CS compared to Kai'Sa. Champs who typically don't take much CS often don't require much CS to be valuable teammates, such as support champions. These kinds of champions are capable of scaling well off of their abilities and first items alone. Yet, champs with a lot of CS, such as hyper-carries, typically require many items to be effective. In either situation, try to do better than the numbers shown here to do well.
The most important items to focus on in your Yuumi versus Kai'Sa build include Mikael's Blessing, Staff of Flowing Water, and Moonstone Renewer. When Yuumi included at least these three items in her build, she did significantly better when facing Kai'Sa than with most other typical counter builds. In fact, Yuumi had an average win rate of 46.4% when playing against Kai'Sa with this counter build.
To have the highest probability of beating Kai'Sa as Yuumi, Yuumi players should use the Summon Aery, Manaflow Band, Transcendence, Scorch, Font of Life, and Revitalize runes from the Sorcery and Resolve rune sets. Of all the rune combinations players picked for Yuumi vs Kai'Sa LoL games, this blending of runes resulted in the greatest win rate. In fact, these runes provided a 46.4% winrate overall.
By default, tips, stats, and builds on how to beat Kai'Sa as Yuumi are given for all ranked divisions combined. To scope the stats and builds to a particular skill level, you can use the selection menu earlier in the counter matchup guide.