Hello everyone, I am Kratos Aurion. I am a long time Magic: The Gathering Player and discovered Eternal about three months ago. I got to Master in Ranked first time last season and have had some good finishes on events such as the Sellsword Event, where I managed to get to fourth place in the Leaderboard with my Mono Time Event Deck When I first tried seriously to get to Master, I got decklists from the internet and just played them as they were. I knew someone else navigated the list to Master, so this gave me some confidence that it could be done using this list, and I focused on learning the interactions and playing the deck well.Soon enough, I realized that this was not sufficient for me. While grinding a deck until I got to Master was certainly possible, I felt like I was not using the feedback I got from my games optimally. I figured out some parts of the deck I liked and some I did not like. I could certainly improve the deck or tailor it better towards the current metagame.I am going to discuss three related lessons I learned about refining decklists this way. The focus will not be about "brewing", that is, starting from an idea to get a deck, but about taking a decklist, an established archetype or an idea of your own, playing games with it, and incorporating the feedback you get from these games.Eternal is a game with a lot of randomness. Each game is unique, and this is what makes it exciting. However, it also complicates the process of drawing conclusions.A very simple example is the following: You play one game with your deck and get power flooded, so you decide that you're playing too many power sources in the deck and cut them down. I'm probably not the only one who has fallen into this trap.The reason why this is a faulty conclusion is that a single game, or even two or three games, actually gives us very little information given the amount of randomness involved. If we look at other areas of life where statistics is applied, 100 or even 1000 samples might be considered a small sample size, yet we try to draw conclusions from a sample size of 1-3.While in this particular example, we can use math to help us find the correct number of power, there are plenty of more complex questions we can ask about our deck where we really need to play games to figure out the answer. Let us assume we want to understand our matchup against one particular archetype. We play against that archetype four times and lose three out of our four matches. It would be easy to conclude that our matchup is quite bad. However, if our matchup is 50:50, the probability of losing 3 out of 4 matches is exactly the same as winning 3 out of 4 matches, in which case we would have drawn the opposite conclusion.The bottom line is that we tend to draw conclusions from way too little information. One of the reasons why we do so is related to our emotions, which leads me to the second lesson.It is easy to get frustrated when things aren't going your way. You thought your deck was great, yet you keep losing. Something must be wrong with the deck.I have a personal anecdote where I was playing my Nictotraxian Control deck and was lacking Fire influence. I stared at all the cards requiring Fire in my hand while I was getting beaten down. After the match, I rushed to the edit deck screen and changed the power base to include more Fire. In particular, I cut the Diplomatic Seal s I had included to guarantee the Influence I need for my early drops since I was frustrated about drawing one late where I was lacking Fire Influence.I made poor decisions about my decklist based on a single game where I had a frustrating experience since I was trying to prevent this from ever happening again. In doing so, I disregarded all my previous experience with the deck where the Diplomatic Seal s had been good. Do I know if playing them is correct? No. However, cutting them due to one bad experience certainly is not.There is no decklist that will never leave you frustrated. Even the most consistent mono faction aggro deck will leave you power flooded sometimes. Once you realize this, it becomes easier to not fall into the trap I described after some frustrating games. Your deck with which you had good results during the last month is not suddenly terrible because you happened to lose three games in a row with it.Learning to separate your short-term emotional response from actual meaningful observations is an important step to make better progress in refining your decklist. In my third and final lesson for today, I am going to discuss a more systematic approach towards this goal.When you are looking to refine a decklist, it is not enough to just play lots of games with the deck. You should instead try to answer specific questions or test assumptions you have about the deck.Let us assume that you are facing many aggro decks and decide to build a deck that should have a good matchup against aggro, such as my Combrei Anti-Aggro Midrange deck. Afterwards, you run into a lot of Control decks and even lose against an aggro deck once, leading you to discard your deck as bad. A better approach would have been to put your assumption to the test and focus on your results against aggro only for the moment. It may very well turn out that your one loss was bad luck and you are, in fact, very happy when your opponent plays Oni Ronin turn 1 against this deck. In this case, you just added a good tool against aggro-dominated metagames to your arsenal. You may want to round it out to improve your overall win percentage later, but then you will need to ask different questions.A more general scenario where asking the right question is important is when you cut a card X from your deck and replaced it with another card Y. Whenever you draw card Y, you should be asking: "Would I rather have this or card X right now?" This will help you identify when Y is better than X, when X would be better than Y, and can eventually lead you to a conclusion on whether your swap was correct.In order to not fall into the trap of small sample sizes when evaluating the answers to your questions, keep track of relevant stats. For example, if you try to answer the question "is a particular card good in my deck?", keep track of the games where you drew it and it was good, where you drew it and it was bad or you never even got to play it, and also the games where you wish you had drawn it but didn't.This concludes my article for today. I have little experience writing articles, so as with the decklists, I try to learn from feedback and improve. Thus, please leave a comment and let me know what you liked and disliked and what you would like to see in further articles.As for specific questions I would like an answer to: Did you like the topic and would you like more similar articles? Would you prefer more detailed examples with actual decklists or do you like the high-level discussion of concepts?Until next time