Xibei San Ma
Hungary has a lot of going things going for it, but there are some negative aspects which impede its success worldwide. The good things:
- Decent research teams
- Right in the middle of Eastern Europe (to make conquest easier)
- High IC relative to size
- Good relations with Germany
- Decent tech teams
- OK military leaders
- Metal surplus
- Excellent ministers
And the bad things:
- Lack of many resources
- All neighboring nations have their independence guaranteed by at least 3 countries each
- Low starting IC compared to some neighbors
- Small starting army
- Low manpower
- Only 2 tech slots
- No navy (unimportant, if you don´t have a port)
You probably won't be able to go to war anytime soon with Hungary. Although you are surrounded by nations which are just aching for a whooping, they have their independence guaranteed by the United Kingdom or Germany. You also have to deal with your shortage of resources -- Germany is a good trading partner, as it needs the metal which you can provide. Alternatively, you can stock up on supplies and trade them for whatever else you require. Since you can't do anything for the first 5 years, that means you have to build up you army steadily until the time comes to go to war. Try not to build any 1918 infantry at the start and focus on upgrading and repairing your army until basic infantry has been researched, at which point you should starting building fairly long queues of 1936 infantry. Try to produce extra supplies so you can trade them for other resources down the road. Focus on industrial technologies and infantry/land doctrines as long as you only have two slots -- the rest can come later. You should have in excess of 30 divisions by 1941, as well as an HQ.
War With Yugoslavia
Only declare war on Yugoslavia after no nation is still guaranteeing its independence. Although Yugoslavia's army should roughly equal yours (although most of the time, Yugoslavia focuses on its airforce and only builds 3-5 infantry divisions, making your job easier. Typically, Yugoslavia has its troops spread around throughout the country, while yours are completely focused on the Yugoslavian border. Your aim should be getting to Belgrade as soon as possible. That means you should blitz through Zrenjanin, Novi Sad, Ojisek, and get to Belgrade before Yugoslavia can organize and effective defense. That would net you 11 of Yugoslavia's ICs (2 in Novi Sad and 9 in Belgrade) right off the bat. From there on, you can pretty much do whatever you want with Yugoslavia. Perhaps seeking to divide the country in two would be the best way to win -- but it's up to you. If this war with Yugoslavia starts when you are part of Axis, try to move your armies quickly to sea, perhaps to Bosnia before other Axis reach it, so you can build navy if you want.
The Vienna Dictate
Shortly after the war with Yugoslavia is concluded, the Vienna Dictate should fire. Germany usually tends to endorse giving Transylvania back to Hungary, so you'll get Satu Mare and Cluj Napoca. Usually, Bulgaria will declare war on Romania if its request for Constanta is denied. Accept an alliance with Bulgaria and declare war on Romania. Romania should not be too difficult to conquer, despite its superior army and IC base, since it is forced into war on two fronts, and your army and Bulgaria's combined should be more than a match. Usually, Romania surrenders, giving you most of Western Romania.
War with Bulgaria
Now is the time to backstab Bulgaria. After it has helped you win the war against Romania, show your gratitude by leaving the alliance with it and proceeding to declare war on Bulgaria. Bulgaria tends to have a fairly small army, so the fight should be heavily in your favour. However, Bulgaria is a mountainous country, so it may not be as easy as it first appears (the best thing is to have some mountain inf. as your spearhead). The best bet would be to take Sofia and the rest of Western Bulgaria quickly. After that, if your army is strong enough and a suitable defensive line in Plovdiv and Pleven does not exist, the rest of Bulgaria should fall quickly. Otherwise, it will take a bit more time.
War with Greece
Going to war with Greece may be a bit tricky. Italy will at some point declare war on Greece, at which point Greece will join the Allies. Since you don't want to be in a war against the United Kingdom and eventually the United States, it may be for the best not to invade Greece. Instead, you can turn your attention farther South.
Turkey and Beyond
The Turkish army should be no match for your superior army by now. You can go through Istanbul and subdue Turkey easily, while giving your air force easy targets to prey upon. From there, you can invade Persia. However, you must first make sure that the Soviet Union does not declare war on you. It may be best to wait until Germany progresses to the heart of the Soviet Union before deciding to declare war on Persia. Persia is strategically important as it is a great source of oil -- one of your only sources, in fact. No blood for oil? Pfft. From there, you have carte blanche to invade -- err, liberate -- Afghanistan. After that, there's not much to do. You can declare war on Germany if they're looking weak, or you can take a shot at the Allies or the Soviet Union.