7.7  DEFEND   The DEFEND action changes the defence mode in a land area to DEFEND, to cancel previous AMBUSH or RETREAT orders. There is no cost in BPs.
Format [ "DEFEND" ] [ FROM WHERE ] [ BLANK ] [ BLANK ]

7.8  ENTRENCH   The ENTRENCH action orders your armies to dig in to defend against an attack from an adjacent area. You can only entrench on one border at a time: if you set a new one then the old one is cancelled. There is no cost in BPs. Entrenchments stay in place from turn to turn, and are shown on your game report.
Format [ "ENTRENCH" ] [ WHERE ] [ WHERE AGAINST ] [ BLANK ]

7.9  AMBUSH   The AMBUSH action sets an ambush (i.e. changes the defence mode to AMBUSH) in a land area against an attack from an adjacent area. Ambushes are remembered from turn to turn, and are shown on your game report. Each area may have only one ambush set at a time: if you set a new one then the old one is cancelled.
Format [ "AMBUSH" ] [ WHERE ] [ WHERE AGAINST ] [ BLANK ]

7.10  RETREAT    The RETREAT action sets a retreat (i.e. changes the defence mode to RETREAT) in a land area, and selects a retreat location to an adjacent land area. If the area is not adjacent then the action fails. If you do not specify an area, then the retreat location is unchanged. Retreats are remembered from turn to turn, and shown on your game report. There is no cost in BPs. See also paragraph 8.7 for how retreats are carried out.
Format [ "RETREAT" ] [ FROM WHERE ] [ TO WHERE ] [ BLANK ]

7.11  RETREAT LOCATIONS   Retreats and retreat locations may be set by using the RETREAT action (see 7.10), but every time that an army moves from one area to another it always resets the retreat location to be the area from which it came (i.e. armies always try to retreat to wherever they came from, unless you order them differently). At the start of the game all areas should have retreat mode set, but no retreat location. It's a good idea to get these set as soon as possible.

7.12  NAVAL BASES   Your ships keep track of which naval base they came from (it's shown in your game report). You can change the base to which some ships belong either by collecting them together with some ships that came from that base, or by moving them into the base itself. When you combine two fleets (by moving ships into an area where you have ships already) then the base to which the combined fleet belongs is the base for the ships that were moving.
If you want to combine two adjacent fleets with the choice of base the other way around, then move a single ship from the fleet that's already in position to combine with the new one before it arrives.



8  BATTLES

8.1  SEA BATTLES   When you try to move to a sea area where there are ships belonging to someone else there is a sea battle, which consists of a single round. Each side takes losses of one third (rounded down) of the number of ships on the other side, and the weaker side also takes losses of one third (rounded down) of the difference in numbers. The attacker loses the battle if the defender is not wiped out. Armies don't count in sea battles, but at the end of the battle if there are fewer ships than armies (due to losses) then the excess armies are lost as well. If the attacker wins the batle then all the remaining ships on the attacking side move into the area that's captured.
There are no retreats, no ambushes and no entrenchments in sea battles.

8.2  LAND BATTLES   Battles are resolved in four phases: air, sea, land and control. The losses on each side in each phase depend on the strength of forces involved, the terrain, the defence mode and what happened in the earlier phases. Fractional losses are ignored (which means they're not added together and not carried over from phase to phase or turn to turn).

8.3  AIR PHASE   In the air phase (in World Empires) each air force loses strengths equal to one third of the strength of the opposing air force (i.e. you inflict one loss for every third strength on your side). See 4.13 for how the number of air strengths on each side is decided. If either side inflicts more losses than the strength of the opposing air force then the extra losses are carried over to the next phase.
There is no air phase in Medieval Empires and European Empires.