A military access (MA) agreement allows one nation's troops to enter and traverse another nation's provinces peacefully.
Requesting Military Access
Each MA request consumes one diplomat. If you want to MA a lot of countries, you should try to increase the rate at which you receive diplomats. It's also a way to use diplomats that might otherwise have gone to waste. Frequently, MA obtained decades before may save your army during a war when you manage to retreat to neutral land.
Some players opine that the stated chance of getting MA is off-base:
- "Likely" (0 or higher) should be "Maybe"
- "Maybe" (less than 0) should be "Unlikely"
- "Unlikely" (varies, but lower than Maybe) should be "When hell freezes over"
Be that as it may, it seems that having relations at 0 or higher makes a big difference - important enough that it is probably considerably more effective (in terms of number of diplomats needed) to Gift the target country to above 0 before requesting MA. Note that each failed MA request causes your relation to decrease (and a successful MA request causes the relation to increase by 10). So keep an eye on your relations and give a Gift if failed requests cause relations to go south. If you don't, you're making it less and less likely, with each request. If relations are above 25, the request is "Very Likely" and permission to MA indeed becomes very likely.
You can also use MA to pre-position your troops for an attack, either on the MA'd country or a neighbor. Just be sure to cancel MA first before attacking a country you have troops in, or it's -5 stability points.
Military Access and Exploring
MA is incredibly useful when exploring. If you get MA to far-flung lands, your ships have a distant base for exploring and repairs. And, of course, you can explore those lands themselves - sometimes to find unowned provinces hidden inland (especially in Africa). Once you find new lands even more distant than your latest base, you can rinse and repeat, all the way around the world. Thus, it's useful for anyone building a colonial empire to know how MA works.
You can explore land provinces with your naval Explorer, if you have MA to the country and the province has a port. Just tell the fleet to dock at the unexplored province, as usual. This is much faster than using a Conquistador, because it's only increasing the time the Explorer takes to go from the adjacent sea province to the port (which is often only a couple of days). Plus, of course, the Explorer gets his "port clock" reset to zero. Unfortunately, this trick does not work for unowned (native) coastal provinces.
To explore the world quickly, scatter a handful of ships and cavalry around the map. As soon as an Explorer or Conquistador has finished exploring a particular area of interest, use an MA'd port (Explorers) or any MA'd or neutral land (Conquistadors) to immediately zap the leader to another part of the world - where some of your other scattered ships and troops have meanwhile gotten into position for the hand-off (and/or healed while waiting). By passing the leader like a magic baton, your explorers will waste very little time criss-crossing known land to get to unknown areas. You can discover most of the world with just 2 or 3 (each) of Explorers and Conquistadors, if they don't die young.