Advance Wars By Web Wiki

Infantry attacking a Md. Tank under Jugger's SCOP, showing the huge (0% - 95%) range in potential attack damage dealt.

Luck is a semi-hidden game mechanic during combat that can cause a small and random deviation in damage dealt relative to the expected damage for an attack. This is almost always a positive modifier with units doing slightly more damage, which is sometimes clarified as a CO having a good luck value. The standard good luck value is +9%, regardless of unit matchup, with any attack doing between ±0~+9% more damage. In Advance Wars By Web, the damage range factoring in luck is always displayed in the attack tooltip and the calculator.

Luck damage is not a modifier for the base damage - it is a flat value with each % representing 1 extra true hitpoint removed from the target. In most cases, luck usually results in considerably more damage dealt than any reasonable firepower increase would provide. For example, a full-HP Infantry will deal 5% base damage to a Tank which, with luck, means the actual range of damage an Infantry will do will be 5%-14% damage - to do even a middling value of 9% damage without luck involved would require a +80% attack boost, which is highly unlikely for any CO to obtain except Grimm during Haymaker. This means that luck proportionally favours units with poor base damage, and in practical terms allows cheap units such as Infantry to be used to efficiently clean up weak units that they would otherwise not be able to effectively damage.

Note that all damage is reduced by defense and when the attacker is at lowered HP (see Damage Formula), which also includes the luck component as well, rounded up in cases of sub-percent values. As such, luck damage will be mitigated by increasing the defending unit's defense (such as a ground unit on a property) or if the attacker has been previously injured. This can be viewed as every 10% defense and 1HP lost from the attacker reducing the maximum luck cap by 1% each. Using the same example above, this means that a 5HP Infantry will deal 2.5% base damage (rounded down to 2%) plus ±0~+5% luck damage.

In the case of SonjaFlak, and Jugger, there also exists bad luck, where units may deal less damage than expected. This exists alongside their good luck value, with both good and bad luck rolling values separately and the sum of their results being used as the end total luck modifier. For example, Sonja rolling -9% bad luck and +9% good luck will effectively cancel out to result in 0% extra damage. Bad luck can result in an attack dealing 0% damage.

Luck rolls are linearly distributed, so for normal COs there is a 10% chance to roll any individual value between 0% and 9%. In the case of COs with bad luck, due to good and bad values rolling independent of one another, their luck distribution follows a Gaussian distribution instead with extreme low- or high-rolls being much less likely than middling values.

While it is beneficial to get high luck during attacks, one should not rely on luck to make or break an offensive.  If one is reliant on a lucky blow to eliminate a unit and rolls low, the opposing unit will be left standing with 1 HP, potentially blocking an entire offensive from progressing if it happens in an unfortunate place.

Below is a table outlining the default luck range and COs with unique luck ranges, and to what degree their luck will extend.

CO Day-to-Day CO Power Super CO Power
Standard ±0%~9% ±0%~9% ±0%~9%
Rachel ±0%~+9% ±0%~+39% ±0%~+9%
Nell ±0%~+19% ±0%~+59% ±0%~+99%
Sonja -9%~+9% -9%~+9% -9%~+9%
Flak -9%~+24% -19%~+49% -39%~+89%
Jugger -14%~+29% -24%~+54% -44%~+94%