Siege anchors defense (top Def +4,680% & HP +4,851%); Ranged leads attack (+5,162%). Attack trails Defense/HP on every branch except Ranged — raising Attack buffs is the lever that turns your proven defense into offense.
Defensive Blazons + Military Academy Def/HP research + Castle Decorations — the ONLY sources of the "Defending" buff type, and the least contested.
Put your best wall general on the keep. Pure-wall #1–2: Zhou Yu, Takenaka Shigeharu. Siege specialists: Hersilia, Irene d'Arneau.
The defense set: +1,170% total buff on the defending general. Prefer Heian for pure siege buffs.
Achaemenidae debuff mayors STACK to −600% enemy attack when they join your defense. Set "Automatic fight for other Cities" ON; Russia culture for trap attack.
Siege 1st-gen beast on your defender (adds Def/HP/%); 2nd/3rd-gen debuff beasts on the sub-city mayors.
Your 29,112 traps swung the last defense. Grow trap count (Trap Factory + research); Russia sub-cities boost trap attack.
"Wall Defense" buff combo on the keep general; Achaemenidae debuff sets on every mayor.
Your Def/HP is already whale-proven; the two upgrades that move your needle: stack flat Siege/Ground Def+HP (immune to enemy debuffs) and weaponize your Mayors’ debuffs to halve their attack.