Empire of the Sun: Erasmus Version 2.0 Goes to War

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When I was working on Empire of the Sun 2nd edition, Gene Billingsley convinced me to create a new solo system for the game. I blithely said ‘sure’ not realizing how much work this would entail and how difficult it is to write computer logic for humans. My history with solo systems goes back to my 20th century release of VG’s Peloponnesian War, so I examined that method for this system. Although I did incorporate the option that once you start with the Japanese, you can switch to the Allies in 1943, ultimately the task required a new solo system.

My more recent experience with ‘Bots came with my co-design of Fire in the Lake, using Volko’s COIN solo system that I reprised in Churchill. I would say that it worked for Churchill, but some felt that it needed more detail. That said, I have become convinced that without a computer program or a tailored App, any solo system for a complex game is still going to require some amount of player input.

Next came Pericles, and I went back to my roots in computer programming and used decision logic diagrams. My impression is this system has been well received and that many gamers, myself included, are getting much of their Pericles table time using the solo system. An amusing anecdote is Michael and Tom from the Rally in the Valley podcast recently reviewed Pericles. During their initial games, I made the comment that if they were using the ‘Bot, they were playing me. The reply came back that if this was the case, I won. I must say that did make me laugh, but it also says that the system is credible as an opponent.

So, now fast-forward to the Empire of the Sun 2nd edition reprint. The natural question is, “What is going to change?” From a core game mechanics and components standpoint, nothing beyond a couple of card typos. However, Erasmus is getting a complete makeover from its initial incarnation. When I look at Erasmus 1.0, I would say that from an opening game play perspective, the ‘Bot plays well. Now that is not to say that a player with full knowledge of both hands of cards cannot manipulate the system, but that in general it plays a solid opening. If you are new to Empire of the Sun, using the ‘Bot as an input will get you over some of your initial learning curve challenges.

The Allies play a solid mid and end game, but I have found that Japanese play in the end game could be improved. From a presentation point of view, Erasmus version 1.0 requires some significant player input for Taskforce activation and such, plus the system can use a bit more explanation with examples. These are the kinds of things that I will improve in Erasmus 2.0. The charts for the Japanese opening are available online at Consimworld and Board Game Geek, so if you are interested, feel free to give them a spin. I am currently testing these charts on CSW with the Empire of the Sun board that has resulted in several version changes; the most recent is version 8. As I write this, my good friend Francisco Colmenares is rendering the remaining charts into this new format.

What I wanted to do in this article is walk you through the first card played by Erasmus 2.0 in the 1942 Short campaign so that you can get an idea of how the system works.

Opening Hands (number is the card number followed by an abbreviated title)


12: Op MI

28: Big Tokyo Express

59: Central Force

23: Op RE

71: High Alt. Interceptors

72: Carrier Conversions

64: Halsey Typhoon


4: Arcadia Conference

13: Op Watchtower

23: PT Boats

51: Chenault

26: Army Ambush

Here is the new Axis of Determination Chart.

The Japanese side’s cards have a logistics strength of 20 or greater, so the strategy chosen is “Aggressive Air Superiority Strategy.”  You get there by following the decision yes/no questions that ultimately lead to ‘G’ and the stated result. The next step is to determine the initial objectives for this strategy. If you examine the “Aggressive Air Superiority Strategy” (Orange box) you will see it has three elements: Neutralize Allied HQs, DEI Surrender, Malaya Surrender. These elements cover the historical Japanese strategy.

If you examine the Neutralize Allied HQs (Yellow box), you will see that the Japanese are ordered to concentrate air units against the Allied HQs in the Philippines and Singapore, with a third choice moot at this time as there are no other Allied HQs in the Dutch East Indies (DEI).

The next step is to determine which Japanese card will be played. One of the things that makes Erasmus far more involved than other ‘Bot systems is Erasmus has to evaluate a hand of four to seven cards and how to use them coherently to achieve a range of objectives.

Here is the card choice decision logic.

In this situation, you will sort through the hand and determine that the two Resource cards are to be held for later in the turn. Subsequent evaluation will show that the strongest unrestricted military card is to be used (choice ‘E’) and within that set of cards, the paratrooper bonus is the tie breaker, so the Japanese will open with ‘Central Force’.

With ‘Central Force’ as the chosen card, next we have to determine which units are activated to achieve each of the stated objectives.

We now examine the Task Force Composition chart that went through some of the most extensive changes from version 1.0.

Task Force Composition chart for choosing units to achieve objectives.

Determining which units are activated is one of the hardest things to script and requires some player implementation of principles, but hard absolute rules are based on calculating various combinations that meet a level of damage requirement, for which there could be many legal solutions. For a new player this is actually not a problem, but a feature that aids learning.

What the Axis of Determination set as an objective is that the SWPac HQ with a reduced FEAF air unit (defense of 10) must be attacked with sufficient force that a .25x result will eliminate the air unit and put the HQ out of supply (OOS). That means, if you look at the damage rules is we need to bring at least 37 or more factors to hit Manila. Singapore on the other hand has a .5x requirement, so we need 36 factors where a .5 combat result will score 18 hits that would eliminate the Malaya (MA) air unit and put Malaya HQ OOS.

Opening Card Japanese Taskforce moves.

These first two attacks can be achieved with most combinations of two strong air units. In the above illustration I have chosen to use 5th Air Division and the 23rd Air Flotilla to attack Manila with 38 factors. Singapore is attacked with the 21st and 22nd Air Flotillas with 36 factors, so both objective requirements have been met. However, you could experiment with other combinations of Surface ships, air units and carriers to get to the same place. There are no wrong answers as long as the required level of attack factors is assembled to attack the objective. You can either choose a legal combination or randomize between the various choices. Just going through this exercise once, something I have literally done a thousand times, will enhance your EotS skills and understanding of the Japanese opening choices.

Now that we have met all of the requirements for the first major piece of the Aggressive Air Superiority strategy, we note that South HQ with the Central Force card generates 6 activations, and we have only used 4 so far. We now need to find the highest priority objective for the DEI Surrender objectives. We discover that Balikpapan is the highest priority. Now we note that to get a 1x result, which is the default, we need a reduced army unit with a +3 modifier or a full strength army. Again there are choices, but since ASPs (Amphibious Shipping Points) are a critical resource, using less ASPs is the better path. So, supporting the invasion (1 ASP) with a carrier naval unit yields a +4 drm (die roll modifier) minus 1 for the Jungle terrain. It turns out that both carrier units in range of Balikpapan are in Davao (Mindanao Philippines), so sending one of the CVLs meets the 1x requirement of generating 9 hits that is guaranteed to eliminate the Dutch regiment with a defense of 6.

The alternate would have been to send the 18th  army (Malaya), and use the extra activation to send the 14th army (Philippines) armies against Tarakan as an alternative. It uses more ASPs (4 versus 1) but captures an extra objective. This is one of the situations where you can experiment or use a random die roll to determine which way to go. In this situation, I have opted to use less ASPs.

To finish out the offensive, you would roll the intelligence die for the Allies whom you are playing and determine your response, or as some folks do, use an Allied Erasmus to see what happens.

So, that is how things work with the new and upgraded Erasmus 2.0. Just to put a punctuation mark on this little exercise, here is how the first turn went on New Year’s Eve.

It turns out that the Allies got ridiculously hot dice, in that I rolled 6 nines (critical hits) over the course of the turn.  As a consequence, the Japanese managed to capture all of the DEI objectives by their sixth card play. The Op MI card enabled a solid Southern defense perimeter (per the chart) in the Solomon Islands and New Guinea, with the seventh card (High Altitude Interceptor air replacement steps) placed in the future offensives queue (FoQ). On the flip side, this first turn saw a rare repulse of the Japanese 18th army in Malaya against the 3rd Indian corps with several elite air units and a CVL reduced by the Allied critical hits. There are no free lunches in EotS. A great way to ring in 2018.

If you want to see more, we are playing a series of matches on CSW against Erasmus, and you can find the charts on BGG and CSW. Overall things are progressing well for the reprint. Have fun…

Mark Herman

Fortress of Solitude

January 2018


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2 thoughts on “Empire of the Sun: Erasmus Version 2.0 Goes to War

  1. Will there be an opportunity to upgrade our components of the most recent edition with Erasmus 2.0?

    Love the decision tree, easy to parse out the behavior of the AI. The prototype seems a little acronym heavy but if the final is anything like Churchill I’ll definitely be happy.