Bouncing Deathquark did an excellent episode on chain bidding, and since I am now more invested in learning Adaptive, I went back to listen to it.

I wanted to make this knowledge accessible to people that don’t listen to podcasts. This is not a transcript, but rather me delivering their thoughts to you in my own words.

Game Theory

You’ve finished your first two games and you’re on to game 3, bidding on the deck that won both first games. Chain bidding is a mini game played before the last game of Adaptive, and the goal here is to gain some kind of advantage for the game itself, by “winning” the bidding. But how do we define winning the bidding?

Imagine there is a theoretical chain number that if applied to the winning deck, both decks become balanced. And by balanced, I mean if you played this match-up 100 times, it will be as close to 50 wins for each deck as possible.

Suppose this theoretical balance point is 6 chains. We can define “winning” the bidding as your opponent playing the winning deck with 7 or more chains, or you playing it with 5 or less chains. You’ve “won” by gaining some form of advantage from the chain bidding process.

Hidden Information

If you and your opponent both “know” this theoretical balance point is 6 chains, and (this is important, and not explicitly stated by BDQ) both players know that the other player also “knows” this, then there is no point in bidding. The bidding will end at 6 every time.

But the reality is that your evaluation of this balance point is going to be different than your opponent’s, and not only that, you of course don’t know what their evaluation is. The assumption now is that you have perfect knowledge of this point of balance, but you’re not sure about your opponent.

A common mistake observed by Kiramode and CoDameron, is players opening bids higher than they should. A player may know the balance point is 6 chains, but since they don’t know if their opponent has evaluated it correctly, they shouldn’t open at 5 chains. They should in fact bid the lowest they can in order to fish out the balance point their opponent has reached. For example, if I evaluated the balance point to be 9 chains, and my opponent has evaluated it at 3, and I open bid at 7 I have lost a potential of getting the deck for 3, gaining an even bigger advantage.

Nathan vs. Brooks

At the finals of Denver Vault Tour, Nathan played Bahamut and Brooks played Bombfoot. Bombfoot won both first games and the players proceeded to bid on Bombfoot. Brooks stated he thought Bahamut was the better deck, and for the purposes of this example(I believe I heard otherwise), Nathan evaluated the balance point at 3-4 chains.

Brooks is forced to open with a bid of 0 on his own deck as per the rules of Adaptive, and Nathan, “knowing” the balance point is 3-4 bids 1. Brooks passes and lets him have it. If Nathan opened bid at 2 or even 3, he would have forfeited the opportunity of getting the deck for 1 chain, a bigger advantage according to his evaluation.

Now as far as I remember, Nathan in fact thought that Brooks would want to play his own deck, and bid on that assumption. Nathan actually also wanted to play Bahamut. The result is that from Nathan’s perspective, he lost the bidding, as he was trying to give Brooks the deck for more chains and ended up with what was in his mind the weaker deck, with a chain.

Pot odds

Low bidding is easy, there is no risk involved, if you “know” that the balance point is 6 chains, you aren’t risking anything by bidding 1 chain. The risk comes when you go above the balance point. Suppose you’ve evaluated the balance point at 3, but you think your opponent might have evaluated it higher. If they bid 3 do you want to risk going to 4?

I won’t go into calculating pot odds, as they did on the podcast, but I think we can all agree that the further you’re stepping away from your perceived balance point, the higher the risk. In the above example, bidding 4 incurs a small risk for a small gain. But if my balance point is 3 and my opponent bid 7, then bidding 8 is risking the 4 chains advantage I already have, for a small incremental advantage. I’d have to be pretty sure my opponent would go to 9 to do so.

As an example, in another finals at Origins, Ben and AJ bid on AJ’s deck. Ben evaluated the balance point at around 5 while AJ evaluated it at around 13. When Ben bid 3 and AJ responded with 6, Ben believe he could push the bid higher, and went to 7, then 9, and let AJ have it at 10. 10 was the point where Ben thought that the chances of AJ going any higher was not worth risking the advantage already gained.

Contact and afterward

On the podcast, Kiramode and CoDameron continue on to evaluating the balance point, but I feel they only touched the surface. They also looked at it mostly from the perspective of an Adaptive finals after an Archon/Sealed event, as it was the most common in US at the time. If you wish to hear their thoughts, I encourage you to give the episode a listen.

This post also doesn’t cover the psychology of bidding, and why making higher bids can be used as a tool.

As always, you can follow me on twitter for updates. And join us at the Sanctumonius discord server if you’d like to chat with me, or join an awesome community of KeyForge players.

I also started streaming on twitch. I am still learning the ropes and I have a lot of dead air time. But I think I provide some useful commentary on the game and my decision making.