Dealing with bombard towers in FFA diplomacy games

I've seen people do poorly against massed bombard towers. Free-for-all games with diplomacy let you trade with other players and discourage attacking, allowing players to build up their bases. Long games can even lead to all wood being exhausted, such as with The Legend of... Blue Coffee Regicide Rumble #2 (G2).

In this game we see teal, as Celts, trying to snipe a king hidden in one of numerous bombard towers, using 60~100 woad raiders. We also encounter the claim that petards can't be used to destroy massed bombard towers even when wood buy price is around 700.

Petards can be used here, but everyone forgot about an important unit: the monk, and especially the missionary as (spoilers) both players at the end were Spanish, and both had over 100k in trade profit. Expert players remember this option with long team games, such as at one hour in on Arabia - The Vikings Post Imperial Hell Part 2, but less experienced players often forget.

I wanted to show how effective monks can be against bombard towers, but due to several mistakes regarding game mechanics, the demonstration was not very effective. Videos are less interesting without voice commentary, so I made a recording on HD and if anyone finds it interesting, they can make a video from it or try the included scenario themselves:

https://drive.google.com/open?id=1uwt02agm_ngmGSoMKKRsa9OmDxSGFcOg

Descriptions of monk mechanics can be found at http://ageofempires.wikia.com/wiki/Conversion#Age_of_Empires_II and https://steamcommunity.com/sharedfiles/filedetails/?id=548698803#1040753.

My mistakes:

• I thought from a little bit of testing in a game that time spent traveling counted against maximum conversion time, but further testing showed this was not the case.
• I didn't realize that formations affect conversion progress, reducing it down to zero just like how trade carts would lose their gold in a formation until a recent HD patch. (Monks who are out of range in a formation and locked onto a target without Theocracy won't lose their faith if that target is converted, while individual monks will lose their faith.)
• I thought that monks with Theocracy retained their conversion progress when a target was converted as long as they don't move. Further testing suggests progress is always lost when a target is converted or dies.

The plan for the recording was simple: have monks charge up their progress on an unimportant building, out of range of the bombard towers, and hidden from the defending player. Send in a few fast units to distract the bombard towers while the monks approach them, and then have the monks insta-convert as soon as they reached the towers. If it was possible to do this on normal monks without even Fervor, it would be even easier with missionaries with Fervor.

As a result I put in more than just bombard towers; I also put in bombard cannons, a castle, and a few cavalry units. The cavalry units ran off to scout, but the remaining units made conversion difficult when insta-conversion failed. Avoiding castle fire requires patrolling at a distance, so I wasn't able to use a single scout as I had planned, because the bombard towers were arranged around the castle and some of them couldn't reach the single scout. The short patrol necessary to avoid castle fire also makes it difficult to avoid bombard cannon fire, even with a square pattern.

I tried to do the recording in a somewhat realistic fashion. Since formations cancel progress, you have to click each monk individually on a bombard cannon in the partial fog of war. The best way is probably to put them in a hotkey group, wait until they've charged for 15~20 game seconds on a building, then repeatedly press the hotkey and select each monk in succession to send to a target building.

Since it's unrealistic to micro 15 monks while also avoiding castle, bombard tower, and bombard cannon fire with three scouts, the plan was to just take out the bombard cannons first so I used four monks. I couldn't be sure the bombard cannons wouldn't switch to the closest target, due to the aggroing scout running away too fast or dying, so I couldn't have a scout in close and therefore couldn't go for any towers. The rest of the monks were supposed to be ready once the bombard cannons had been converted and a scout was close to the bombard towers, but I forgot so they lost all their conversion progress.

It's a lot easier when you have 10~20 units to act as the distraction and they can take more than two castle volleys each. You would want the patrolling units to be close enough to the bombard towers to attract their attention when the unit they saw earlier dies. You would also want to send in more units after the distraction has been set up, to stop any enemy melee units from reaching the distracting units. Rams work if they stay alive, which may require separating aggro from bombard cannons or mangonels. This may be possible by using some kind of threat to force them back 6~8 tiles, then sending in rams to within range of the bombard towers, then sending in cavalry towards the enemy siege so they aggro the cavalry instead of the rams, which are now following them.

You could also set your monks or missionaries up to go as a wave, given enough enemy buildings. Start the monks furthest from your opponent converting the building next to them, then work your way towards a few closer groups. After ~10 in-game seconds, go back to the first group, quickly hotkey them, then as fast as you can send each individual monk towards a tower without ever asking them to move in formation as a group. By the time you finish giving orders to the last, and closest group, they should have been converting for about 20 in-game seconds.

Then repeat the process with closer groups of monks. They should end up traveling as a compact wave, but with orders to convert many different towers. Your main army is waiting at the front of the wave to go in first.

I'll also mention sending in units to draw away defenders from a position, and the standard flanking maneuver. Useful when using cavalry to pick off siege defended by pikemen or enemy cavalry. At one point in the linked game, a player with champions was trying to kill some markets defended by teutonic knights. They could have just lured them away. In another game, a player had died but their units were still close to several relics. This could easily have been lured away. Somewhat related is sending a small group of cavalry some distance in front of the main group, so that auto-firing onagers don't hit the middle of a large group. Against scorpions, the distracting units would run obliquely, so they stay alive. An important tactic against massed scorpions such as in AoE2 - Cannon Boar Nothing!.