Besiege Wèi to rescue Zhào (圍魏救趙／围魏救赵)
When the enemy is too strong to be attacked directly, attack something they cherish. The idea is to avoid a head-on battle with a strong enemy, and instead strike at their weakness elsewhere. This will force the strong enemy to retreat in order to support their weakness. Battling against a tired and dispirited enemy will give a much higher chance of success.
Make a sound in the east, then strike in the west (聲東擊西／声东击西)
In any battle the element of surprise can provide an overwhelming advantage. Even when face-to-face with an enemy, surprise can still be employed by attacking where they least expect it. Create an expectation in the enemy's mind through the use of a feint. Manipulate the enemy to focus their resources somewhere before attacking elsewhere that is poorly defended. Tactically, this is known as an "open feint".
Sacrifice the plum tree to preserve the peach tree (李代桃僵)
There are circumstances where short-term objectives must be sacrificed in order to gain the long-term goal. This is the scapegoat strategy where someone suffers the consequences so that the rest do not.
Take the opportunity to pilfer a goat (順手牽羊／顺手牵羊)
While carrying out one's plans, be flexible enough to take advantage of any opportunity that presents itself, however small, and avail oneself of any profit, however slight.
Stomp the grass to scare the snake (打草驚蛇／打草惊蛇)
Do something unaimed, but spectacular ("hitting the grass") to provoke a response from the enemy ("startle the snake") to have them give away their plans or position. Do something unusual, strange, and unexpected to arouse the enemy's suspicion and disrupt their thinking. It is more widely used as a warning: "[Do not] startle the snake by hitting the grass". An imprudent act will give one's position or intentions away to the enemy.
Has anything like that ever happened in your games?