3 refers to the three sets of twin princesses you’ll have under your power. To save you from the politics of the plot--which are both hard to translate and rather boring—I will just say that the three countries surrounding your kingdom are being jerks (or were you the first to be a jerk, who cares). Upon acquiring each set of twins, you’ll be able to train them in SLG style gameplay. If successful, you should at least have one foreign country at your beckon, but there has to be a way of getting all three.
Contains data from VNDB, available under the Open Database License. Reading difficulty and script measurements come from jiten.moe. Statistics are based on daily data dumps and may not reflect real-time changes.