It’s a very interesting strategy, and I think it deserves further exploration! I hope someone plays it against me as Britain, so I can test it out. :-)
I think the attack certainly works very well if you achieve total surprise.
German Naval Problems
What if your opponent sees it coming? One initial problem with this “low-investment” G2 attack on London is that without a Baltic fleet build, the Allies can either shoot down or lock in your sole remaining transport near Gibraltar. If you move the German Med fleet to the east coast of Gibraltar (inside the Med), then the Allies can send a sacrificial destroyer (either British or American, whichever survives) to the west coast of Gibraltar, and now you can’t get to the coast of the UK until your non-combat move of G2. You could try to knock out both destroyers with your 2 German subs, but you only have about 36% odds to wipe out both destroyers, and you’re increasing the risk that the American transports will survive. On the other hand, if you move the German Med fleet to the west coast of Gibraltar, you have to do that on G1 non-combat (after you’ve sunk the British cruiser in the Western Med), so you will not wind up owning Gibraltar, so the USA will be able to attack your BB with 1 ftr + 1 bmr (60% odds for Americans to sink your transport). So it’s not guaranteed that you’ll be able to set up the G2 attack at all; you might have no transports in range of London.
What Germany Gives Up to Setup the G2 London Attack
I agree that it is relatively easy on G1 for Germany to land its entire air force in range of London on G2. I think the real cost for the German war machine is sending the Mediterranean fleet to take Gibraltar on G1, which I see as suboptimal. The only way you can get Gibraltar is by using your transport, so now you are not attacking Egypt G1, and you are not reinforcing Libya on G1, either. You can’t even land fighters in Libya, because they’d be out of range of London. So either you pull out of Libya altogether, or you let Britain attack Libya with 1 inf, 1 art, 1 tnk, 2 ftr vs. a maximum of 2 inf, 1 art, 1 tnk – Britain has 84% odds to win that battle. Either way, you’re not likely to ever take Egypt, let alone the rest of Africa. That will seriously hurt the German economy as the game goes on.
What Britain Gives Up to Defend Against the G2 London Attack
My battle calculator is showing that the UK can defend against a G2 attack of 1 inf, 1 arm, 6 ftr, 2 bmr by buying something like 3 inf, 1 ftr for the UK, lwhich still leaves enough cash to buy 1 inf, 1 art for India. Assuming the USA flies 1 bomber to London on US1 (and why wouldn’t they?), that gives the UK 5 inf, 1 art, 1 tnk, 1 AAA, 3 ftr, 1 bmr in London, which means 64% odds for London to hold the capital. Even if the Brits lose the capital, the Canadian transport has excellent odds (82%) to retake it on UK2 with 1 inf, 1 tnk vs. 1 tnk , and the Germans are very likely to lose at least six planes while taking London (88% chance), so taking London isn’t going to do that much for the German position vis-a-vis Moscow, even after collecting London’s 30 IPCs of loot.
What Happens if Germany Follows Through
Assuming Germany follows through with the G2 attack even after seeing the UK build 3 inf, 1 ftr in London, then in 4% of games, Germany will take and hold London for a full turn, which is probably enough to win. In 32% of games, Germany will take London for one turn and then immediately lose it. This will cost Germany most of its air force, as well as the chance to take Egypt. India will be somewhat weak against Japan, but Russia should have enough breathing room to temporarily reinforce India until the UK can get back on its feet. Alternatively, Russia can pressure Germany hard in Leningrad, Ukraine, etc. so that even if India falls, Germany will be in trouble from a 100% KGF by turn 5 or so. This “average” outcome has interesting opportunities for the Axis, but on the whole I think the position favors the Allies, especially if there is any kind of Allied bid. In the remaining 64% of games, the Axis don’t even manage to take London, and the Axis disproportionately lose planes in the attempt, while also giving up Egypt and likely exposing the Axis Mediterranean fleet to an easy UK2 kill (e.g., 3 ftr vs. 1 BB, 92% win for UK).
What Happens if Germany Chickens Out
If, on the other hand, Germany decides not to make the G2 attack after seeing the UK build 3 inf, 1 ftr in London, then it’s not obvious to me that Germany has enough compensation for its decision to ignore the African theater on G1. German fighters in France are out of range of Egypt on G2, and you can’t safely stack Libya if you’re setting up for the London attack on G1, so your max G2 attack on Egypt is something like 1 inf, 1 tnk, 2 bmr, 1 BB. Britain can defend with 3 inf, 2 ftr, which gives the UK 64% odds to hold Egypt. Even if Germany wins that battle, it will almost certainly cost Germany at least one bomber, and Germany will only have one tank sitting in Egypt. There will be British forces in Libya, Jordan, and Sudan that can take Egypt right back.
Meanwhile, Britain is down one fighter in London (the cash that ordinarily would have bought a second fighter in London was instead used to build infantry) and one infantry in India (Britain only had enough cash to drop two land units in India on turn 1). On the flip side, Britain is effectively up one fighter in Egypt (because Germany wasn’t able to kill it on G1), and up three infantry in London (because Britain bought extra infantry for defense).
Granted the infantry in London aren’t quite as useful as the infantry in India, because they aren’t going anywhere until Britain builds a fleet…but assuming Germany chickens out on G2, there’s no reason why Britain can’t build a fleet by UK3 at the latest. Those infantry will eventually be put to use invading Norway, France, NW Europe, etc. Plus, there are three infantry in London to compensate for the loss of one infantry in India. Plus, a fighter in Egypt is arguably more useful than a fighter in London. So, when you add up all the effects of defending against the G2 London attack, at best, Germany has put Britain very slightly out of position, in exchange for basically giving up on conquering or even looting Africa. I’m not saying that the missing infantry in India won’t ever be the margin of victory for Japan – sometimes Japan will be able to capitalize on the one missing infantry to take India a turn earlier – but more often, I think Germany will regret sending so many resources to the west.