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What a game demands for a win: Skill, Luck, Yomi

Games demand different things from the player for a win. This post tries to categorize these into Skill, Luck and Yomi, giving some non-scientific definitions and examples.

EDIT: After some research and helpful comments, I learned about this great gameplay blog, which describes “Skills” with a DKART-system (dexterity, knowledge, adaption, reflexes, timing). In my opinion there is much more to it, as for example team communication is a very important skill, and some meta-skills like focus,patience, selfcontrol and determination are very important to become better at a game (or, for that matter, anything).


Original post here.


Due to the interest in the game theory of the first post, I will talk about another concept that I use. Instead of deepening the broad statements made, I will add more broad statements. Huzzah!


So today I want to classify games on another scale, this time with three axes: Skill, Luck and Yomi. The scale describes what component is needed to consistently win the game. As an overview, quick definitions:


Skill is everything that is trainable.


Luck is everything that influences the games outcome, that can not be influenced or predetermined by any player of the game.


Yomi is the ability to know or to have a high probability of guessing correctly what the enemy player will do next, before anything can actually physically be known.



Skill is everything that is trainable. Eye-hand coordination, analysis and thinking, self-discipline, team communication, etc. If you put 10.000 hours into it, you will be better. If you set your mind to it, focus on the development and practice, you will become better. Experience, intuition or book knowledge all help you understand and act more precise and efficient in whatever you are doing that needs Skill.




Luck is everything that influences the games outcome, that can not be influenced or predetermined by any player of the game. One gameplay implication of luck (most of the time) is the need for risk management, which is a skill though. The more impact singular instances of luck have on the games outcome, the higher the game would rate on the luck scale. For example, poker, though having a lot of luck involved, actually is not that much about luck. The cards sometimes might screw you over, but due to the frequency of singular lucky moments, it is much more a game about risk management, bluffing and knowing people. “Snakes and Ladders” is based solely on luck. The board game “Risk”, while it has risk-management in its design focus (and in its name), is based heavily on luck, because luck is what decides the game in the end. Because of this, I am not to big a fan of Risk (and because of its chaotic mechanics).




Yomi is the ability to know or to have a high probability of guessing correctly what the enemy player will do next, before anything can actually physically be known.

Yomi is a weird thing. It is very arguable whether it is trainable. There are some psychological tricks you can use to win Rock Paper Scissors more frequently, and there are people who for some reason are better at RPS than others. But in the end, when two players, who both know all the tricks by heart and are not influenced by any of them, play RPS against one another, one of them still can be better with statistical significance. I don't know how that works. Maybe it's magic. Maybe it's telepathy. Maybe it's empathy and psychology; maybe it's just another skill. I don't know. The important thing is, it's not luck. Another thing about Yomi is, you need another person; Yomi doesn't work against a computer.


Ok, given these three scales, games can be differentiated on them; and some interesting observations about the dimensions can be made. First, let us look at very extreme examples:


Snakes and Ladders: High Luck, No Skill, No Yomi.

Due to the lack of decision making in the game, it's based entirely and solely on luck.


RPS: Low Skill, Zero Luck, High Yomi

Except for a small barrier of psychological tricks, that have to be dealt with, RPS is a prime example of a Yomi game (at this point, the term “Yomi” has reached its limit, lol).


Go: Zero Luck, Zero Yomi, High Skill

Go has no random elements; and since you place one stone after another and make no hard decisions at the same time, Go, at least on my level, has no Yomi. Maybe if you're really, really high up, and if you are on a very equal skill level to your opponent, maybe then it has some element of Yomi; but I doubt that, and for the purpose of this analysis, we might say it has no Yomi. But Go involves skill, very focused skill. You can become better at go all your life, there is always more to learn and train, and the training will always show in better games.


Counter-Strike: High Skill, Little Luck, Some Yomi.

I'm talking about pro-level CS, not about your general LAN-Party-playing-once-a-year-CS. On a low-level, CS seems to have lots of luck involved; but that is merely due to the player's lack of knowledge about the game. CS needs different skills: reflexes, 3D aim, squad tactics, knowledge of the weapons and maps, and team communication. The better you are at each, the better you are at the game, simple as that. Because of its real-time structure, it has quite the strong element of Yomi in it. Do you go to bomb spot A or B? Do you wait a second in front of a door, or do run fast in hope that the enemy checks a different corner when you meet? Another interesting concept opens up at this observation. For this CS to really have a high element of Yomi, you AND your opponents need a good foundation of skill. Yomi only works against people of equal skill; otherwise one player is just flattened. If you're a much better shot, you will kill him even if he pops up behind you.


StarCraft: Next to Zero Luck, High Skill, Some Yomi.

Now on this scale, StarCraft has a very similar structure to Counter-Strike. Except for small deviations in damage output, hardly anything in SC is random; everything is very predictable and influenceable by the player. Though a good, albeit obvious point can be made with this example. The skills demanded by StarCraft are quite different from CS. SC needs multitasking, macro-strategy, micro-tactics and unit-handling, knowledge about various strategies, tactics, units and counter-tactics; of course, in a team game, team communication; and, often overlooked, very tight 2D-Aim and generally quick, precise input over mouse and keyboard. After having learned the general structure of the game, the first thing to really let you grow in skill is learning to use hotkeys and multitasking, resulting in ramping your APM (actions per minute, any input from mouse clicks to keyboard taps) from 60 to 120 to 200. The average pro-player has APM from 350 to 450, because the game demands it.


A game can not only be highly based on skill, but also the kinds of skill can be very different. Go needs different skills than StarCraft, which needs different skills than CounterStrike. A game can demand more skills than others; StarCraft demands a broader range of skills than Go. I would call this “skill focus”; what skills are needed, and how broad they are set. The demanded skill set is mostly what makes different players like different games. If you like fast reflexes, go with ego shooters. If you like multitasking, go with RTS. If you like precise analysis, go with Go (ha.), etc.


Risk: High Luck, Some Skill, Zero Yomi.

Three very good examples that demonstrate the implementation of Yomi are Risk, Diplomacy (<a href: DevLog1 >which I described earlier</a> and Street Fighter. First, Risk is, as mentioned above, heavily based on luck. You can have the best strategy and still be screwed by the dice. There is a lot of risk-management involved, some diplomacy with the other players, and maybe a little bluffing. But Risk has zero Yomi. Because every player decides one after another and no hard decisions are made at the same time, there is no place for Yomi.


Diplomacy: Zero Luck, Some Skill, quite high Yomi

Diplomacy on the other hand, while having no random element, heavily implements Yomi. You have 15 minutes every round to discuss strategies and politics with your opponents and temporary allies, and in this time you write down your moves. After this period, all moves are executed at the same time. Do you believe France, and support him to go into the English canal? Or do you think he will move into your Ruhrgebiet, and you will have to block him there? Or, an even better example, since this is a little clouded by bluffing (in contrast to Yomi): You will have to take Norway or Sweden for the win; the Tzar, as your last standing opponent, has an Army in Finland; and your Fleet is in the Skagerrak. Both of you have access to both countries, both of you can only go in one country, and if you move into the same country, you will block each other and stay in Finland or respectively the Skagerrak. Basically: If you choose differently, you win. If you choose the same, you lose. You can do all your RPS psychology tricks, but at the end of the day, its Yomi. It's not luck. It's not Skill. It's Yomi.


Street Fighter: Some Skill, High Yomi, Zero Luck

Last example, that shows a quality of Yomi, is Street Fighter. Street Fighter needs a lot of practice for the perfect execution of whatever special move you want to do, a lot of timing and experience with the different characters and tactics; I would argue it's not quite demanding in Skill as StarCraft or Go, but it definitely beats both in Yomi. Block above or down. Attack fast or slow. Retreat or close. Street Fighter is pretty much exactly like Rock Paper Scissors, except you throw five rocks, five papers and five scissors at nearly the same time against your opponent. In comparison to Diplomacy, the Street Fighter Yomi is very, very fast paced; in fractions of seconds there are several instances of Yomi; whereas in Diplomacy, there are maybe two every fifteen minutes, and they are not even guaranteed. So there is very slow, very thoughtful Yomi, and very fast, reflex-based and intuitive Yomi.


Another fun thing that can be observed in Street Fighter, is the Skill Growth / Success Growth relation. When playing the game for the first time, you just button mash. Press any buttons and some half-fitting directional keys, and you win or you lose and its fun. Due to the missing knowledge about the game, it might as well be a luck-game. But then you sit down, choose a character, and learn to execute the special moves. You know how to Hadoken or you know Chun Lis spinning kick that looks like a Helicopter ( <3 Chun Li). And after an hour or two of learning, memorising and practising these moves you play against a button mashing noob again... and lose. Consistently. Trying to play the game better at that point actually makes you play worse. After a week of practice or two, you get the hang of it, and learn to block and counter random kicks and punches, and to follow with your own combo; from then on, it's continual growth. But for a short time, the growth of your skill was inverse to the growth of your success rate. Also fun: Over the course of learning the game, the game “changes” from luck based to skill based to a Yomi based game. Only on a high skill level does the dimension of Yomi in the game open up.


Now that we have set and explained the dimensions, I want to write a little about my own preference and reason, and how I try and implement this in UnderRaid.


I am not a fan of luck. Luck is a game designers tool, and should only be used sparingly. It can be used

- to break up boring, fixed parts of the game; I believe, that is what the small deviations in damage in StarCraft are for (especially for the early game, where very few units battle);

- to implement the need for risk-management, if that is a skill that you want your game to be based on;

- to implement some sort of comeback mechanism; though, as I will demonstrate in another Log, Luck is the worst, un-fun mechanism for that.


Too much luck makes the game chaotic. If you battle for a long time in whatever game and in the end you win or lose solely based on luck, it just doesn't feel like a deserved win. If you lose due to luck, it doesn't feel justified. Risk management might be core to the game, but the end should not be decided by luck, but by the level of risk management. I really enjoy it if a game is designed in an interesting way that does not rely on luck at all.


Yomi is a much, much more satisfying way to end a game. If you lose by a dice roll, you could also won, without anyones doing, only by the arbitrary will of soulless dice. If you lose or win by Yomi, then you defeated your opponent. You both knew the possibilities, you both decided, it's a focused showdown between two spirits. A win by Yomi, at the end of a long, equally skilled battle, feels epic; and a loss feels good and deserved. While I'm at it, neither Yomi nor Luck are the last word in game design, of course. Yomi might be just another skill needed; if on a high skill level your game demands Yomi, at least know it and decide for it.


When designing a game, I think it's very important to think about the skill set your game demands. Play your game and try to think it to the extreme, and what skills and actions are needed to win. Are all the skills needed really what you want from the game, or can you focus it more? Does it need another level? While I enjoy RTS games, I just stop at the point where I'm needed to have higher APM, and for that matter, extreme multitasking. I enjoy well thought out strategies, but actually, that is not what RTS games are about at some (my) mediocre level of skill. I always thought Risk was about strategy and diplomacy; but it is much more about risk management, and the diplomacy depends heavily on the other players. The board game Diplomacy is much more focused on the strategy and diplomacy, and even brings qualitative players to negotiate and lie. For that matter, I really like it if a game focuses its skill set; because then I can really concentrate and enjoy that skill, rather than doing five things half heartedly.


Having said that, we try to focus UnderRaid on the tactical decision making and the strategic adaption to the enemy (rather than simple execution of a previously devised plan), with a little Yomi in between. With the fast turn-based gameplay, neither precision nor high APM are needed; we try to keep the mechanics simple and intuitive; so neither the game nor the controls are your enemy, and the game comes down to the interaction of two players. In the picture you see UnderRaid between StarCraft, Counterstrike and DotA; due to the room-selection we are a little heavier on the luck than StarCraft, and the strategic adaption is heavily yomi-based as well as some tactical components.


Dear reader, thank you for reading all these broad statements without scientific aspiration.


Until next time, just play whatever you feel like



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