Triplanetary… play by forum


I don’t have a physical copy of Triplanetary, because they weren’t shipping outside the USA., and buying from Warehouse 23 to the UK is ridiculously expensive (a $50 game would cost me, after customs and fees, well over $100. (That’s a separate rant for another place.) But it’s still an interesting game, the rules can be had without charge from the official site, and it’s not too hard to find out what the map looks like (hint: it’s on the kickstarter page). I’ve written software to take a list of ships and vectors, and plot images.

So does anyone fancy playing by forum? I’ve run one game by email so far, so it probably shouldn’t be anything too complex, but I can support genuinely hidden units (with a separate map for each player if necessary). I’m happy to referee (if there are hidden units) or play. Ultimately I’d like to work up to the campaign game.

(I have a complex RPG session to run on Saturday, so I won’t start actually setting things up until that’s done.)


raises hand and scratches his crotch to reach the minimum post character limit


Right then. First, get a copy of the rules: . Next, note a couple of amendments:

  • If a ship begins its turn in a gravity hex and remains there for the whole turn (i.e. it is stationary and does not apply thrust), it is affected by that hex’s arrow as if it had just entered that hex. If the arrow is Weak Gravity, it may not be ignored; it still takes effect, as though it were Normal Gravity. This is an exception to the normal rule that ships are affected by gravity hexes only when the hex is entered.
  • Takeoff is modelled as an acceleration from a planet hex to a gravity hex adjacent to that planet (directly above the base at which the ship is located), which does not consume fuel points or allow overloading. As the ship enters the gravity hex, its velocity is reduced to zero in accordance with the general principles of astrogation. Next turn it may apply thrust; if it does not, it will fall back to the planet and crash. It may thrust to enter orbit in either direction, to land on any side of the planet, or to move into a non-gravity hex to commence a journey. Overload manoeuvres may be used if these would otherwise be permitted.
    (Therefore, to expand on this: a minimal takeoff and departure consists of, on turn N, using boosters to move from a base to a gravity hex and ending up at speed zero; on turh N+1, applying one or more thrust to get velocity away from the planet.)
  • A ship “in orbit” is one with a vector that will carry it, at speed 1, from one gravity hex to an adjacent gravity hex of the same body.
  • To land, a ship must be in orbit or stationary adjacent to a planet, and must apply one thrust; it may land on any hex side of the planet (but may only take off again if that hex side contains a base). It is not possible to land as part of an overload manoeuvre.
    (Therefore, to expand on this: a minimal approach and landing consists of, on turn N, entering a gravity hex and adjusting velocity so as to be in orbit or at speed zero; on turn N+1, having perhaps moved one hex round the orbital path, applying one thrust to land.)

Unless you fancy something more complex, I recommend we first try out Bi-Planetary, the Mars to Venus run - a fairly short scenario with no combat, just manoeuvres. Other players are welcome to join in too. Pick a colour for your ship marker, and decide which way you want to run the race.


Exciting! I’m just going to have a quick read of the rules and I’ll post back later.


Okay, I think I’ve got it. Is purple an option? If not, I’ll go for red, and I’d like Venus-Mars please.


OK, here’s the setup:

Your ship is “N”. If I remember to update it, the bottom right figure on the counter will change to show remaining fuel.

Also note the compass rose for unambiguous directions.

I have a course I’ve used before in this scenario, so I’ll use it again. Launching in direction C.

Your decision for turn 1 is basically: in which direction do you want to launch?

(hmm, that’s not very helpful. Click on the image to get the full thing.)


Perhaps unsurprisingly, launching direction F


Also, surely you should get a fuel reduction or speed penalty for using a cheap substandard crappy Martian corvette instead of the far superior Venusian beauties, sleek as a fish.


Ah, yes, those streamlined fish…

More to the point:

R: thrust D.


N: Thrust A (just in case we came up with the exact same route (unlikely, given my maths), it’s going to look like I copied you, isn’t it? Maybe I should post my whole proposed route under a ‘spoiler’ tag. I don’t want any Martian bastards denigrating the tactical planning skills of the heroic Venusian drones!


I’ve taken a phone of my planned route with a current date stamp just do I can prove it, if it comes to space court


Dashed arrows indicate current velocity, i.e. where you’ll end up if you don’t eat your peas apply thrust.

To make it harder to read accidentally…

Thrust C.

(use the cogwheel icon and “hide details”)


Okay, I’m confused… aren’t we at velocity 0 when we are in orbit? Which means the next turn we would be in the same spot (ignoring the gravity) - so in my case, wouldn’t thrust A put me in the hex above Venus (just outside the gravity well)? Or are we moving at velocity 1 when in orbit?


I understood that leaving the gravity well put us down to velocity 0, you see.


It’s just that the way you’ve plotted it, it’s as if we were moving at velocity 1 directly away from the planet in our last turn. Am I making sense? I’m sure I’m wrong but I can’t see where, did I get the velocity going to zero wrong?


Yes, I’ve messed up and counted an extra velocity hex for both, because I misread my course notes. Let’s hit that with a big stick and try again.

R turn 1 overload thrust, C+D; N turn 1 thrust: A. Which gets us to this start-of-turn-2 map:

to which I’m adding a thrust C in turn 2.


Ahh, phew! Thrust F for my next move


Added your turn 2 F, my C, and corrected fuel:

R turn 3 astrogation

burn D


I forgot overload :frowning: never mind! Thrust A


Turn 3: R burns D, N burns A.

Turn 4

R coasts.