Talk:Sappers/@comment-65.28.183.104-20190615024624

Excluding its effects on lumberjacks and wood gathering, Sappers is a very situational technology. Although it says it gives villagers 15 bonus damage against buildings in game, this is misleading. It gives both 15 bonus damage to Buildings (not Standard Buildings but Buildings) and Stone Defenses. This is important as Standard Buildings are not subject to the bonus Building Armor from Masonry and Architecture while Buildings are. Given that Harbors, Outposts and Towers are both Buildings and Stone Defense, this grants villagers +30 damage against them.

Villagers themselves have a +6 bonus damage to Stone Defense and +3 to Buildings, which, combined with their base attack of 3, grants them up to 12 damage against Harbors, Outposts and Towers. Combined with Sappers, this total reaches 42 damage prior to resistance and armor, 46 for Inca Villagers with all upgrades and 48 for Spanish Villagers with Supremacy. Towers are the most obvious target for villagers as even a Keep with Masonry and Architecture has only 5 Hack armor and 6 Resistance, meaning that 'average' Villagers deal 31 damage per strike. This can be as high as 39 for civilizations without Masonry and Architecture such as the Aztecs, Byzantines and Vietnamese.

Walls and Gates also count as Standard Buildings and Stone Defense, however they have heavy armor and resistance. A Stone Wall has 8 Hack armor and 16 Resistance, meaning it would eat up 24 of that 42 points of damage, though 18 is still a sizable amount. Fortified walls have 12 Hack Armor and 24 Resistance, eating up 36 points of damage, resulting in villagers only dealing 6 per strike. Gates, both normal and Fortified, have 6 Hack Armor and 20 Resistance, resulting in Villagers doing 16 points against them. Simply add 4 and 6 to the totals for Inca and Spanish Villagers respectively.

Whether or not you research this technology depends on your civilization. It seems like it'd be a no brainer to do so for Spanish and to a lesser extent Incas due to their villagers having bonus attack, armor and in the case of the Spanish, health. However it could also be useful for the Persians given their villagers are created 20% faster in the Imperial Age, they are the only civilization to lack the Two-Handed Swordsman upgrade and given that they have a very strong economy. This thus makes training extra villagers to engage in sapping viable.

Sadly, neither the Berbers nor the Indians have access to Sappers as both civilizations have Villager bonuses (10% increased movement speed for Berbers, costing 25% less in the Imperial Age for Indians).