For as long as humans have been describing warfare and battles we have described the ebb and flow as first one side and then the other gains the upper hand, pushing their opponent back across the battlefield (or, in the larger picture, across the map.) However, I don’t think any accounts of such events have ever really lent themselves to a true understanding of just how battle lines can shift within the duration of a fight.
Prior to the development of the modern firearm and the introduction of armored vehicles, a battle line was very much a line. A mass of men armed with melee weapons and short range projectiles, occasionally aided by archers and/or cavalry. The two sides faced up against each other and bashed each other in the face. Depending on the situation, it might have been tightly formed lines such as the Roman legions or Greek phalanx, where only the first few lines were actively fighting at any one moment, or it might have been more loosely formed, where the two masses became wholly interspersed amongst one another (as seen in Braveheart).
Early modern firearms still relied on massed lines of men, but that was because of the inaccuracy of the weapons and because battles usually still resorted to hand-to-hand combat.
Both of these periods saw tactics in which reserve units were sent to reinforce ones’ own weak lines, or to overload weak spots in the opponents. The attacks and counters in this manner are what led to the forward and backwards movement of the fighting across unprepared (lacking significant constructed defenses) battlefields.
Even into the 1900s, hand-to-hand combat was quite common, despite the increase in accuracy of firearms. Bayonet charges were quite common in both WW1 and WW2. However, in WW1, battles were often dependent upon the ability of one side to gain control of prepared defensive positions, making it a much more static environment in terms of what could be gained and lost. Attacks were often made with multiple waves of infantry charges. If an attack failed, the defender had not lost any ground and the attacker had not gained any.
By WW2, the days of inaccurate, low rate of fire weapons were gone. And as a result, so too was the day in which two groups massed on a field and fought face to face (if they could help it). The nature of the war had one side utilizing infantry distributed amongst prepared, static, defensive positions and artillery with mechanized reinforcements, while the other used a combination smaller individual units of infantry supported by armored vehicles, aircraft, and much more accurate artillery and naval fire to help overcome heavily prepared defensive positions. Because of the less solid nature of the lines of combat, the ebb and flow of the battles were much less obvious (to anyone who wasn’t actually in the middle of it all).
The modern development of video has given us the ability to record and see just how lines of combat ebb and flow. But because of the shift away from massed front lines, there isn’t much chance for us to actually view the ebb and flow of a battle. And most cameras brought to the front lines of a combat zone are usually in the thick of things, not getting a bird’s eye view of the larger situation. But the last few days have presented us with something we’ve never had before. A top-down look at fighting between two large crowds primarily armed with melee weapons and simple projectiles — rocks and molotov cocktails. The clashes between the anti-government protesters and what seem to be government controlled thugs have been recorded and broadcast by several news agencies who have set up their cameras on balconies, high up in nearby hotels.
In the clip below, the government thugs have maneuvered some trucks across the road to provide themselves with some cover, and to force the protesters back into Tahrir Square. However, the protesters attack and push the thugs back. There are numerous similar videos available if you can find them, where you can see first one crowd flowing forward and the other backward, and then the process reverses. At one point the group attacking the protesters sends people up into a nearby building to throw rocks and brickwork down on the protesters. At various points, the attackers pushed the protesters all the way back into the square, but by nightfall the protesters had pushed out to the end of the road and set up makeshift barricades (which I have been calling Mubarricades in my head), to defend themselves from the rocks and molotov cocktails which were being hurled at them. I asked a couple of folks on Twitter who are in the military and/or study military history and didn’t get any affirmative responses that there is any video from earlier conflicts which show this back and forth. It’s definitely something that might be of interest to the military, riot police and security forces. And anyone who might be contemplating any popular insurrections as well.