DYNASTY WARRIORS 9 Empires

You can set secret plans at the start of your battle to try to turn the tides. More become available after a few battles so you may not be able to get this achievement straight away, just play the scenario out until one appears in the pre-battle screen. I'd recommend choosing one with 1 star difficulty if you are just trying to get the achievement, but higher difficulty secret plans have a bigger impact upon the battle to help you win.

Once your secret plan is in use at the very start of the battle there will be flashing red or blue icons on the map and some information on the right side of the screen, you will either need to kill some units, take some bases or protect some units in order to complete your plan within a time limit. Rush straight to these locations and fulfil the criteria as fast as possible, as this will help you in your battles to make the enemies weaker and easier to beat.

Once you have completed the plan just win the battle to get the achievement.