Cavum

Plays: 4Px1.

Cavum is a game by Wolfgang Kramer that I have been interested to try for quite some time. The remark that sparked my interest is that it's a very open platform that gives players much freedom to be creative with their plays.

The Game

The setting is that players are miners digging tunnels, establishing mining stations, mining gems, selling them, and setting up presence in cities. Despite the many elements of the game being associated with various aspects of gem-mining, the game is actually quite abstract. It is a tile-laying game. Players are establishing a complex network of tunnels and using it to collect gems to score points. They do this by laying various types of tunnel tiles onto the gameboard. You don’t really discover gems. You decide where the veins are, and once a vein tile is placed, some gems are placed there to be mined by the players. Other than veins and tunnels, you also place dynamites, which blow up at the end of every round and can significantly alter the board situation. You can establish stations on tunnel tiles, which claim such tiles for you and blocks others from passing through. You can also establish stations in the five cities along the edges of the play area. Cities are basically strings of hexes of different lengths. They are mainly used for scoring points.

The big central area is the mountain. The orange sections surrounding it are the five cities. The smallest city with 5 hexes (opposite) is the start city and already has four X tiles next to it at the start of the game. There is also a yellow gems mine with all nine yellow gems at the centre of the board. The other cities are of sizes 6 and 7.

The game is played over three phases, and every player has 12 actions per phase. On your turn you must use between 1 to 4 actions, and when you use them up, you are out for the rest of the phase. Your last action of a phase must be the prospecting action, which means collecting gems by tracing an uninterrupted and unrepeated path from one of your stations to another. This is a very crucial action which you must plan towards. You not only need to plan for the prospecting of the current phase, you also need to think of those in future phases. Stations are very important because they secure your path and also block others’ paths.

The player board. The pieces on it are basically the 12 actions you get to do in a phase. At the moment the dynamite tile is still missing (top right corner). What type of dynamite tile you get for a phase depends on player order. The top row are the various tunnel tiles, the dynamite tile being just a special type of tunnel tile. In the bottom row, the three cubes are the mining stations (one action to place one). Next is the gem vein. In the 3rd and 4th positions are jokers. Swap them for items in a common pool on the game board, or discard them for 3pts each. The last action is the prospecting action.

Above the player board you can see that I have completed a contract, which would give me 28pts. If I can’t complete it, the penalty would be 4pts.

The green player can make a prospecting run starting at the station to the upper right of the white gem vein. Pick up a white gem, then a dark blue gem, go through the next station to the yellow gem vein, then go straight to the red gem vein, and finally end the path at the station to the upper right of the red gem vein. Four gems in total can be collected. No tile is passed through more than once.

There are three main ways of scoring points - fulfilling contracts, selling loose gems and setting up stations in cities. At the start of every phase there are some contracts made available to be claimed. Each contract shows what gems are required to fulfill it, the points it it worth, and the penalty for not being able to fulfill it by game end. Contracts are probably the most important way to earn points.

Two contracts. Gems sold via contracts fetch on average $7 or $8, which are good prices.

At the end of every phase, for each of the six gem colours, players compete for the rights to sell loose gems by bidding the lowest prices they are willing to sell at. The gem market value in Cavum is determined in a similar fashion as Power Grid. For each gem type, there is a track numbered 1 to 9, and at game start a gem is placed on each space. The market value of a gem is the lowest visible number. E.g. four gems are on the board (on veins) or have been mined by players, the current market value would be $4. When selling loose gems, the highest price you can sell them at is the current market price.

The price track for the dark blue gem. The current market price is $6. Once a dark blue gem is sold (be it as a loose gem or as part of a contract) it is returned to this track, and the market price becomes $5.

City scoring is done at the end of every phase and once more at game end. If you have an active station in a city, you score a number of points equal to the number of empty spots in that city. A station is active only if it is connected to another station belonging to the same player in the mountain (i.e. the main play area). If it isn’t, that spot is treated as empty for scoring purposes. This means a city is lucrative when few players have presence, and the later you add presence, the less incentive there is, because you are not gaining many points, you are only reducing the points of other already present players.

The Play

I played a four-player game, and all of us were new. We weren’t too sure what to do, and initially greatly underestimated the importance of turn order. By phase 2, we realised that going later likely means a vein would have run out of gems by the time it is your turn to do prospecting. Whenever a vein tile is placed on the board, only 4 gems are placed. Once the gems run out, the vein is removed. It is important not only to bid for turn order, it can also be important to use your actions quickly (i.e. use the max of 4 on your turn) so that you can use your prospecting action before the others. That was the situation in the second half of our game. Since I had read the rules beforehand and taught the game, I did well in phase 1, completing a contract and shooting ahead in points. However in phase 2 I missed the boat on many gem veins because I was late in turn order. That was painful.

Around mid game. We have connected to the opposite end of the start city.

Dynamites are a mandatory action. Every phase everyone will get a different dynamite tile (to be precise, a tunnel tile with a dynamite). That tile must be placed onto the board. The tunnel on it can be used, but at the end of the phase you know the tile will blow up, destroying all adjacent tiles and the tile underneath which are not veins and do not have stations. Oh yes, it is possible to place a tile on top of another, with the condition that the tile on top must have more exits. Veins can be placed on top of other tiles too. The rules for tile placement are a little tricky to fully grasp at first, because there are many options as well as restrictions, depending on the tile type. The board situation can change a lot not only during the dynamites explosions, but also during prospecting. When a vein is exhausted, it is removed from the board, and the tile below is revealed and becomes effective. A vein is considered as having 6 exits, but the tile underneath may not be a 6-exit tile. Connectivity can drastically change. Dynamites can be used offensively, but are only effective for the next phase (explosion is at the end of the current phase). You can to cut off opponents’ access to cities, or disrupt their ideal prospecting paths.

The green gem vein in the bottom left corner has been blocked off from me (green) by the blue, yellow and red stations. If I want to connect to it, I would probably need to go via the white gem vein and create a new path on the left side.

Ang bid much for turn order, and also took many more contracts than the rest. I thought he was being overly optimistic. However he managed to meticulously plan for a very impressive prospecting path in phase 3, and collected a lot of gems. He eventually won by a mile. In hindsight I should have taken at least one more contract. Contracts guarantee reasonably good prices for gems. In our game, only a few loose gems sales fetched good prices. Most loose gems sold cheaply eventually. At game end, all loose gems must be sold, and these were all sold at rock bottom prices.

The Thoughts

I quite enjoyed Cavum. Many complained about how drastically the board situation can change, which makes planning futile. I disagree. The game is all open information, and I think despite the game being very dynamic, there are many opportunities for players to plan and to strategise. There really are many options and possibilities - how you can develop your network and chart your path, and how your opponent may try to disrupt your plans. You need to try to take advantage of where your opponents place veins. It is a lot of fun trying to work out an ideal prospecting path.

The city scoring is an interesting diversion. There’s a bit of groupthink. If only one player goes for the cities, he’d be raking in a lot of points. However if many go for the cities, the cities devalue, and the effort spent become less and less worthwhile. Loose gems sales is interesting. If you can sneak in some loose gems at high prices in the early or mid game, they can be a great steal. E.g. not many other people have a particular kind of gem, and those who do want to keep them for their contracts. However the risk is getting stuck in downward bidding wars or ending up selling these loose gems as low-demand stock at game end.

Cavum is definitely not a family game. It’s not the type of heavy Eurogame where you have many aspects to manage (i.e. width). However it has good depth. There are many possibilities, and it does feel very open indeed. You are given the tools (each with some quirks) and a blank canvas to plot your strategy. The only random element in the game is the order that the contract cards turn up. Most of them will be drawn sooner or later, and only a few will not be used in any one game. The game may feel quite tactical due to how the board situation can change at the end of every phase, but I think it is more strategic than tactical. You need to consider and plan for the many possible ways your opponents may play.

I think Cavum is among the best of Wolfgang Kramer’s heavy Eurogames.