Strategy for Platinean War

Platinean War Strategy for Brazil

Played as Brazil in normal/normal

Here is some tips:

When the game starts, strategically redeploy all of your movable ground units to Curitiba. Evacuate all naval and air units from Porto Alegre to São Paulo. Avoid any naval battle and head straight to port.
Capturing Concordia after Argentina captures Porto Alegre will leave any Argentinian armies in Porte Alegro stranded. Destroy them.
Do not produce any factories or infrastructure. Focus on producing infantries at all times.
When the US offers its assistance, do accept. Although German will also give reinforcement to Argentina, the US will send more troops.
Focus on annexing Argentina. If any other countries declare on you, ignore them until Argentina is gone. The horrible infrastructure in Amazon jungle will slow them down.
Don't liberate Argentina. Although it gives you a mighty ally and practically will make the whole of south america your puppet (as Bolivia and/or Peru are easily annexed and liberated), it will get 16 victory points, leaving you with a maximum of 29/30 victory points, if you annex all other nations, your allies included. To have a mayor victory you need at least 40, or 30 VP's for a minor victory.

Played as Argentina against AI:

Use naval transport to quickest effect. Move infantry units across as needed across the country (i.e. from Neuquén provice to closest port, then embark to frontlines; same with cavaly and infantry down south). Also, you could try amphibious assault on unprotected provinces.
Research basic construction - this will allow your non-moving units to dig in.
Order some engineering brigades - you will be doing some fighting in river country.
Keep a strong naval presence. Carry out naval interdiction missions as close north to the Brazilian coast as possible. Also decouple "Aviación del Ejército" air group and have the naval bomber wing carry out interdiction on its own (avoid flying it close to ground-based fighters).
Watch who you ally with: accepting an alliance with Bolivia (territorial claims on Chile and Paraguay) will automatically earn you two enemies on your borders, while not adding too much to your alliance. Bolivia is still a good commercial partner even outside the alliance.
Watch your back: expect Chile to jump into the war anyway and assist Brazil by late 1942. Aim to have mountain infantry back on the border by November 1942 (sea transport or redeploy as needed) as stopgap; then move more infantry divisions in for the offensive. After done, you may move them back to business in Brazil.
Watch out for the Chilean Battleship, it may be transferred to the Brazilian Navy and do some harm after you think you are safe.

Kick hard and early. You can punch into Curitiba by concentrating your attack force at Concordia. The AI has apparently not read the above strategy for Brazil but your mileage may vary if playing against a human.
Minimize a two-front war as much as possible. Defeat Chile as soon as possible after they join Brazil. Attack Santiago, then Antofagasta and annex. As all goes quiet on the western front, you may focus on Brazil.
Keep Recife as a major strategy objective (this may mean rolling through the coast: São Paulo, Rio, Vitoria, Salvador) as this is where US reinforcements arrive. Note that these will keep coming for as long as the enemy controls Recife.
Taking the coastal path to Recife will deny the enemy some of his major industrial base.
By the time you have Recife, strategy should shift to rolling westwards and acquiring the remaining victory point provinces. Annex when done.
Note that the 40 VPs needed for Strategic Victory must be owned by Argentina itself , not by the alliance as a whole. Therefore, after defeating Brazil, you might be forced to declare war on one of more of your allies in order to achieve Strategic Victory.