Rainy is a map that has been around for a long time, and has been regularly used in various competitions. As a result, many might find playing on this map tiresome, but I hope I can still raise some interesting points about gameplay on this map. For this purpose, I have artistically made the following picture to make my explanations easier to write and understand.
As you can see, I have assigned each relevant property-pair a letter, with the exception of X and Y, since these are the two main contested properties of Rainy. All explanations will be done from the perspective of Black Hole, for the sake of simplicity.
1) General Map Layout
Rainy has a 2-base vs 1-base + airport setup, where the side with the single base is meant to fall eventually, but can last very long due to the mountain range and the vast amount of movement-restricting forests. This keeps the 2-base side on edge, since he has to take care of covering everything against copters, while protecting his somewhat vulnerable HQ without losing grip on property Y. 15-16k income per turn means that players can constantly afford 2 vehicles per turn in the midgame, barring repairs, massive amount of copters, Md tanks or mechs. Overall, games on Rainy can take (and have taken) very varied forms, ranging from total stalemates to nearly even base-trades. In general though, games end with one side breaking the 1-base front of the other player while holding his own.
2) Capture Phase
Rainy does not have the most complicated capture phase and it is hard to mess up majorly, but as always the art is in the details. On the two-base side, the first infantry will go for the neutral base, while the second infantry can go for either G (and then F) or H (and then I). Personally I prefer property H, since the backwards infantry does arrive at the front faster and this move is not vulnerable to a recon sitting on property F. Sending two separate infantry for H and I is a waste, and two infantry for G and F is only necessary if the infantry that finished capture of G can interrupt the opponents capture of C (or rather it's equivalent).
The infantry that finished capture of the neutral base can head for either J or Y depending on what the opponent did and on what CO you are. If the opponent can't disrupt your capture of Y without harming his own capture phase, go for Y, otherwise J is preferable. The third infantry from the starting base will generally head for E, and everything else just rallies to the front.
On the single base side, matters are a bit more complicated. Since the first infantry should capture as many properties as possible (most likely two) to preserve capture phase efficiency, the options on first glance are A (then airport), B (then C) and B (then E). A (then airport) has a huge advantage due to the fact that the infantry finishing airport capture does this just in time to disrupt the opponent's capture of X, so this is nearly always the preferable choice. Choosing this route, the second infantry should head for C (to secure this property before the opponent can disrupt it, and assist in fighting for X), the third to C and the fourth to D. B (then C) has the advantage that only 3 infantry in total are needed for this front to capture everything, but you have bigger problems fighting for X, and you risk having the capture of C disrupted. B (then E) is an even more inferior version, since you divert one infantry away from your weak front and have no business whatsoever at X.
Another popular option is rushing for X, which gives up funds in total, a problem it shares with every opening that rushes for contested properties on any map.
Faking C first and going for HQ as Sami is fairly nasty, but counterable by going for F first (first meaning after the neutral base) from the 2-base side, making it possible to sit on the HQ if Sami does move towards the HQ. If you don't do that, Sami can go inf-inf-recon from the single base, which you can't counter once she is on your HQ.
3) Midgame
Once the midgame starts, which means for me that vehicle fighting becomes the most important part of the game, the flow of the game depends on what happened with X and Y. Oftentimes they will remain neutral, in which case the first fighting will remain around that area. It is not possible for me to dictate exact moves anymore, but there are a few things to pay attention to. Losing infantry in this stage of the game can be pretty deadly, especially for the 1-base side. If you try to capture the property, don't get all your infantry attacked in the same turn. Don't park your tank on the neutral property if you are the one-base side, since attacking it from the forest still ends up in an 8-6 (unless the opponent has no backup for his tank while you do, for instance if he tried to be smart with a preemptive AA). Similarly, you should avoid having your capturing inf (no matter which side) killed by tank + inf with another tank/inf sitting on it.
What works out best is to time its capture with the purchase of a copter. Since an Anti-Air can't reach the contested property in one turn, you are guaranteed to end up at least 6 infantry HP ahead while denying the opponent the property for even longer. Moreover, the copter greatly restricts movements and generally stalls any sort of advance for a bit. Just randomly building the copter works too, but is a bit of waste. So try to squeeze out whatever infantry HP you can by either starting to capture or interrupting your opponents capture, ideally killing the infantry. A common motive is to move over the copter from your weak to your strong front while building a new copter. Most players will try to counter that by building more copters themselves, but I recommend moving an AA over yourself if possible. Reason is that not being able to OHKO copters can end pretty badly.
If X and Y were captured, or the game goes on for a while without them being captured, the focus shifts a bit towards the general area around C. Reason is, if the 1-base side loses control over C (control not necessarily being capture, it is enough if he can park tanks on it), the game can be over very fast. It allows the attacker to connect his army from beyond the mountain range (between X and C), limiting the usefulness of the defender's copters while leaving him on crappy terrain, as well as usually disabling the airport. Therefore it is of utmost importance to not have whatever is on that city be stupidly killed, and once the opponent can afford to push your parking unit away with an arty, you should have an arty in position as well. Or even better, use an arty to prevent him from being able to do so. Or keep threatening X (if it belongs to him/stayed neutral) to divert part of his forces. Threaten his HQ if he concentrates to hard on X. Stay active, and don't let him just push wherever he wants, be it the area around X/your airport or the area around C.
Another minor tip: don't go arty first, and don't build too many of them. Arties are good and cost-efficient and necessary, but if you have too many of them and your opponent knows his thing, you will be too slow to push down his lone base due to your immobility. Not building enough tanks also does not abuse the weakness of having 1 base on a front, namely not having enough meatshields.
An option as certain COs (Sami, Adder, Koal) is to pump mechs. They are slow, but COP makes them powerhouses, and they can waltz over mountains. However, I'd only recommend this if it isn't important to have the immediate fighting power of tanks (and to a lesser extent infantry) right now. Such situations are for instance if X and Y do have (different) owners already, and/or the opponent goes for a slow arty push from his 2-base side.
4) Lategame
Some games on Rainy can go into a state which is often called "stalemate", usually a result of players refusing to build tanks, defensive reinforcement of the weaker front or one player wanting to drag the game out due to his CO choice. If you are in such a game, there are several things you can do. First off, realizing that "stalemates" can often times be broken, it is still possible to make mistakes or outplay the opponent. Generally, everything that is not covered by an indirect can be an attack opportunity. Attack it and plant indirects behind your attacking unit (without exposing your indirects too hard, hopefully). It is also possible to not shield your arties in certain circumstances if the opponent doesn't have enough to attack into it, so do that to gain position. Lastly, you can gain control over the middle area, using smart positioning as mentioned before, and then focus on one front with your units. As a result, half of the opponents army will struggle to get into good position (especially true for indirects) and you might be able to deal a fatal blow.
All the above tips are applicable for all "stalemates". True stalemates only happen when gaining position becomes impossible, which usually takes a while longer than people like to think.
A more map-specific detail about the lategame of Rainy is the airport placement. It is not impossible for the 2-base side to lock the opponents airport (with an AA or even a missile), in which case building a stealth is a pretty nice autowin. Even if you don't do that, the front around X/Y can sometimes shift towards the airport, now putting the defender in a weird spot since he has to take care of that area too.
Another lategame situation which interestingly enough is not a stalemate, is the base trade. Doesn't happen too often, but it is nice to know what you want to do in these situations. Most importantly, preserve at least some infantry so you can capture the opponent's undefended properties fast. Especially on Rainy, send stuff to capture the opponent's D+E as soon as possible, while defending yours as soon as you can assure that the opponent's single base will fall. That holds true especially for infantry, as long as you still have intact ones on the front. If neither player gets or holds a substantial advantage in this period, you will have to live with the fact that it will stale for real this time, because Rainy wasn't meant to be played from left to right.
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For the end of this post, I have a little quiz for you. How many games did I play on Rainy already? Winner gets a cake.
Best regards, Hellraider
