Tactics are about contrasting your strengths with your opponent's weaknesses and not exposing your weaknesses. Necessarily, it's also about keeping your opponent guessing as long as possible about what's going on.
So here are some examples:
Other tactics still without explanations:
The idea:
To ensure that the opponent only comes from one side and does not stab you in the back, a closed line is formed across the full width of the field.
The effect:
The opponent adapts to the shape of the lines. One's combatants concentrate on the front of the line, which on the one hand increases their concentration, but on the other hand lowers their circumspection.
What goes wrong:
The idea:
The tactic is based on the fact that one side of the line is significantly stronger, and thus a breakthrough should be created. The other side must hold (defensively) during the time.
The effect:
Often the left side is strengthened because often the right flank is stronger anyway and so can hold its position more easily. Also, it confuses many opponents when deviating from convention (= right strong) with a strong left flank.
For the spears, it is easier to act from the left because they can stab to the right and hit into the open shields. The preponderance on one side leaves the enemy outnumbered and easier to defeat.\
What goes wrong:
The Idea:
People are taken out of their own line and placed behind the line as reserves.\
The effect:
One's own line stands looser, which leads to fighting outnumbered. Mostly this motivates additionally because it depends on each fighter. On top of that, each fighter has more space to act.
The reserve can create a new moment of initiative. For example: prevent breakthroughs, create a breakthrough at the opponent, reinforce the flanks, …\.
What goes wrong:
The idea:
The line is divided into steps and placed backwards. To each step, there is a reserve, and to each gap an attack column.\ The reserves do what reserves do. The attack columns attack when the steps are passed sideways by the enemy.\
The effect:
By moving the steps to the rear, the opponent cannot bring his groups to bear immediately. Thus, an additional moment of control is gained. If all reserves are moved behind the front most stage, immense pressure can be created there, while the rear stages are preserved as potential threats.\
If the opponent engages in descending the steps, he finds himself exposed to the danger of the attack columns.\
The corners of the steps are quite attackable, however, it often requires a lot of coordination on the opponent's part. An attack at such a point from the stairs can often create a breakthrough.\
What goes wrong:
The idea: Forget about it!