Advance Wars: Dual Strike/Banker Hills

Introduction
Banker Hills is quite an interesting map, but deceivingly difficult. This is mainly due to the enemy CO, Hachi, who has a nice 10% cost reduction on all units, which becomes 50% during his CO powers. The fact that he can purchase units at half price during these moments is quite disheartening, but fear not! Our strategy behind this map is very unconventional, and borderline A/S-rank, but quite amusing. We will be going for the one-turn capture of his HQ via Sami's SCOP.

Setup
Although Sami does have her lovely SCOP which allows for instant game winners, she does have other nice advantages in this map. All the valleys and pathways here are 1 unit wide, and bordered by mountains. This situation is perfect for Sami's mechs to rush enemy armored units. Also the fact that there are 3 missile silos per side means very slow early capturing (due to infantry hp reduction). However, Sami also captures incredibly fast, meaning we can still 2-turn capture neutral bases despite these pesky missiles.

My recommended skill set:
 * Mountaineer (mountain attack +10%)
 * Invader (capture +1)
 * Star Power (power meter fills up faster)
 * Slam Shield (direct defense +12%)

This set up is mainly focused on quickly getting Sami's SCOP, while enhancing her infantry/mech units with additional defense/capture. Mountaineer is our offensive rushing assist.

Strategy
Our objectives:
 * 1) capturing the two neutral factories north of your starting position
 * 2) capturing as many additional neutral cities as we can
 * 3) holding defensive positions at the central valleys (vertical bars of the $)
 * 4) keeping 1-2 mechs within range of Hachi's HQ for the SCOP

First few turns, build plenty of infantry/mech units. You should be able to capture both factories within 3-4 turns despite Hachi's missile silo barrage. I would build a mech 2nd turn to capture the north factory, while sending your first infantry to capture the other one. On turn 2, move your infantry toward the missile silos.

On the topic of missile silos, I would recommend you attack any of Hachi's capturing infantry, as we want to prevent him from accumulating funds early on.

After your first 3-4 turns of infantry/mech, I would build an APC to send infantry over to the right end. Meanwhile, continually build a mech at your northern factory and send him into the mountains directly north of it. These will be the ambushing mechs.

At this point, things are going to get chaotic. Hachi probably will have a tank/artillery pair, while you only have mechs/infantry. Don't worry. Use your infantry as bait to lure his tanks into the valleys. Then attack with your mechs. Don't worry about taking artillery fire as well - we actually want to roughen up Sami a bit so she can get her SCOP quickly. Once you find yourself in somewhat good position, you can build some of your own tanks and artillery.

By this point, try to hold the central valleys with tank/mech/artillery support. I would sneak your APC + 1-2 mechs from the right side and just drop them off into the mountains directly below Hachi's HQ. Make sure these units do not die! You may have to deal with some of Hachi's own infantry here first, but this shouldn't be to terrible.

When Hachi does use his CO powers to purchase Midtanks/Rockets, I would not panic, but if an opportunity reveals itself, attack his rockets with your tank(s). Ignore that midtank for now. If it happens to reach the middle valleys, rush it with mechs and chip away at its health. Your mechs are cheap and fairly effective.

Repeat this process until your SCOP is ready. If your 1-2 mech way out on the right side are still alive, make sure they are within 5 spaces of his HQ. Its recommended you use a mech here because they have a mountain movement of 1, where as infantry have 2. Use the SCOP, and you should get the instant win!*


 * if Hachi has units stationed on his HQ, hold off the SCOP and get some more mech units nearby in order to take it out during the SCOP.

Summary
Estimated time of completion was 16-17 days given my semi-defensive/offensive pace. If you happen to attack more recklessly/take more casualties, your SCOP probably will be ready sooner, but you'll sacrifice some technique points doing so. This method has only managed an A-rank (275) for me, but it is borderline S-rank, so given possibly a more careful pace, the technique stat can be raised w/o compromising speed significantly.