The IS-6 may not seem like a tank with a great deal of armor by looking at it’s listed stats. However, it’s armor scheme makes good use of angles which results in excellent protection. Keeping in mind that the IS-6’s armor is mainly based on the angles associated with it. Areas not angled are usually the weakest spots to aim at on the IS-6. This guide for World of Tanks IS-6 weak spots breaks down its armor into individual locations based on armor thickness/angle. Factoring in both thickness and angle gives us the effective armor(EA) value. This is the actual thickness that your rounds will need to penetrate.
Frontally the IS-6 is a formidable foe to come across for most tier 8 tanks and lower. Most of the frontal hull armor is difficult to penetrate due to it being heavily angled. The best spot to aim at on the front hull is the lower glacis that sits at 199mm effective armor. Otherwise you will want to aim at one of the turret weak spots. The cupola is only 150mm-177mm effective in the center area. The roof can also be overmatched by 91mm+ caliber guns.
If you find yourself being face hugged by an IS-6. You can simply fire down into the upper glacis since it isn’t very well angled. Try to avoid the slightly thicker driver’s hatch(110mm) since it is tougher than the upper glacis(100mm).
World of Tanks IS-6 Weak Spots – Side View
While the side armor is still angled decently the thickness drops enough to where almost the entire side is weak enough for most tanks that regularly face the IS-6 to penetrate it. The exception is a few small locations on the front of the IS-6’s side hull and also a few small spots on the turret. Some tier 6 and 7 tanks might struggle with reliably penetrating a couple areas if you get a low penetration roll but otherwise the IS-6’s side armor is easy to damage.
Much like the side armor the rear armor on the IS-6 is very weak and easy to damage as long as you avoid the tougher spots on the rear turret.