Networking Zeus IV
by Paul Barker
The Zeus IV variant is interesting in a number of ways. It has a polar projection and a complex juxtaposition of seven powers. A fleet can make a circuit of the outer provinces in seven moves. When I received details of my Zeus IV gamestart in Spring Offensive ("Kadesh") I took a closer look at the map and kept constantly changing my mind about the way that play might develop. This variant appears to be potentially very fluid and interactive. Some of the players in Kadesh have played Zeus FtF and they will support this. This article suggests a way of starting to pin down the interactive geography of Zeus IV, though the methodology is of universal application to Diplomacy variants. Apologies to the other players in Kadesh if I repeat what I have already written to you. Apologies also if I leave it to you, the reader, to draw more conclusions yourselves than you would normally find in a strategy article - I am, after all, playing my first season of this variant.
Before examining the relationships between the positions in Zeus let's look at the regular Diplomacy board. There are seven powers, some are "next to" each other and are therefore candidates for early conflict and interaction. A network can be constructed easily once the criteria for what constitutes a node and a link have been decided upon.
The nodes are obviously the different powers. For the purpose of this article I have decided that a link exists between two powers if either or both of the following can happen in the first year's moves:
1. a unit of one power could move to a home supply centre of the other power;
2. units of both powers could move to take the same neutral supply centre.
Links therefore exist between, say, France and England, but not between England and Italy. Figure 1 shows the resulting network for regular Diplomacy. This is, if I remember correctly, the same as one of Alan Calhamer's networks in a Games and Puzzles article many years ago. It shows germany as having the most central position in the network with Turkey the most isolated. This network does not hint at the Lepanto relationship. As the years pass different networks will evolve (together with different types of adjacency, some of which are "one way"). What one does with this type of network is up to you; the anorak wearers among us can work out all kinds of indices and see how various key moves would reverberate through the network.
Anyway, let's return to Zeus IV. The rules are virtually the same as Diplomacy, for instance normal convoy rules are used. Key differences are the choice of unit type at set-up in the Autumn 1939 special turn, land transit across Pacific island areas and the split nature of Great Britain. The latter posed the main problem in constructing a network. I decided to treat GB as one node.
Figure 2 shows one of the possible representations of the Zeus IV network. Great Britain is the core power, being adjacent in one way or another to every other power. The links have been worked out for all possible legal placements in Autumn 1939 (I hope).
Figure 1 has 12 links and 7 nodes; the beta index is therefore 1.71 (12 divided by 7). the beta index is one of the simplest measures of network connectivity. It is found by dividing the total number of links (or edges) by the total number of nodes (or vertices). the higher the beta index, the higher the connectivity. Figure 2 has 15 links and 7 nodes; the beta index is therefore 2.14 (15 divided by 7). This supports the idea that Zeus IV is potentially more interactive than regular Diplomacy.
The following Tables contrast the number of links each power has with the number of units it starts the game with. It can be seen that there is a closer correlation between links and centres in Zeus IV than in regular Diplomacy and it could be argued that a high degree of correlation must help play balance.
Figures 3 and 4 show the above networks slightly differently. The solid lines now show what I shall term Home Links ("HLs"). These correspond to my first definition of linkage (ability to occupy a home supply centre in the first game year). The broken lines shoe Neutral Links ("NLs"). These follow my second definition of linkage (ability to take the same neutral centre in the first game year). Different types of interaction should occur between powers that are linked by NLs than HLs. Both regular Diplomacy and Zeus have 9 HLs. Zeus has three more NLs (12 to 9).
If we define a Double Link ("DL") as the existence of both a HL and a NL, both games have six. Every power in Diplomacy has at least one DL (Russia has three). In Zeus the USA has no DLs, whereas the Soviet Union has three.
I won't attempt to draw any conclusions from these models in case I start to give away my game plan (if only there was one!). One avenue to explore is the position of those powers which are not adjacent to your power. This type of network analysis can obviously be used to try and make sense of other variants, but don't let grand strategy overshadow the importance of communication.
Reprinted from Spring Offensive 8