BGA Auction Rules
There is a lot of confusion about how BGA auctions work. However it was implemented in a very smart way which saves you lots of time, comparing to order based bidding approach. This page tries to provide a detailed explanation with examples. Without further ado, let's start!
2 player game
We have Player_A and Player_B. Each player can bid some amount of VPs to a faction. There are 2 possible scenarios here:
- They bid higher for different factions (Scenario A)
- They both bid higher on the same faction (Scenario B)
Scenario A
| Player | Ambass | Firaks | Cost |
|---|---|---|---|
| Player_A | 0 VP | 20 VP | 0 VP |
| Player_B | 10 VP | 0 VP | 0 VP |
Both players prefer to play with different factions => they both are paying 0 VP to get desired faction. Then BGA framework adds 10 VP to each => game starts with both players having 10 VP.
Scenario B
| Player | Ambass | Firaks | Cost |
|---|---|---|---|
| Player_A | 0 VP | 20 VP | 10 VP |
| Player_B | 0 VP | 10 VP | 0 VP |
Both players think Firaks are better. Player_A agrees to pay up to 20 VP, Player_B agrees to pay up to 10 VP. Player_A is getting Firaks and pays for them 10 VP (bid of the Player_B).
It is now time to jump to a tricky territory :)
Bid values relate to each other
| Player | Ambass | Firaks | Cost |
|---|---|---|---|
| Player_A | 0 VP | 20 VP | 10 VP |
| Player_B | 100 VP | 110 VP | 0 VP |
When bids are calculated only relative difference between bids is checked. In the above example Player_B is ready to pay up to 110 VP to get Firaks and 100 VP for Ambass. You can read it as:
Firaks are stronger than Ambass. I am ready to pay (110-100) = 10 VP for Firaks comparing to Ambass
In other words, the bids for Player_B can be simplified to:
| Player | Ambass | Firaks | Cost |
|---|---|---|---|
| Player_B | 0 VP | 10 VP | 0 VP |
It means that Player_B gets Ambass, and Player_A pays 10 VP for Firaks. Even though Player_B bid 110 VP for Firaks.
To make your life easier always bid 0 on the weakest faction. This applies to 3 and 4 player games as well.
VP price
If your RELATIVE bid is higher than the other player's bid, you will pay the amount of VP the other player bid. Let's look at Scenario B again:
| Player | Ambass | Firaks | Cost |
|---|---|---|---|
| Player_A | 0 VP | 20 VP | 10 VP |
| Player_B | 0 VP | 10 VP | 0 VP |
If Player_A bids higher than Player_B, it doesn't matter by how much — they will always pay 10 VP (the bid of Player_B).
Key points from the article
- When both players bid higher on different factions => nobody pays VP
- Bids are relative to each other (you should always bid 0 on the weakest faction to simplify your calculations)
- Your bids are telling everyone how much VP are you ready to pay in comparison to other factions. You might end up paying less than your bid.