Some pieces of Armour can be granted a fractional DEF bonus. Examples can be seen on the example Adventure Sheet on page 16 of the rulebook.

As far as I can see, there are only three ways to obtain this (in Book 1 at least), i.e. Finer 0.2 DEF, Greater 0.4 DEF, and Superior Amour 0.6 DEF on the TA, TB, and TC Treasure tables.

How are partial DEF values treated? Do you

(a) Round; so 0.2 and 0.4 round to 0, while 0.6 and 0.8 round to 1.

(b) Truncate; so 0.2, 0.4, 0.6, and 0.8 all truncate to 0.

(c) Apply fractional damage, which might result in having 19.6 HP for example.

As written it seems you apply fractional damage, which is fine, but I would like to confirm if this is the case. Many Thanks.

You can stack DEF bonuses from different equipment parts. So if you have, let's say, two equipments 0.2, and one equipment 0.6, your total will be +1 DEF. If you have +1.8 DEF i would consider it as +1.

That's how i understood it.

When a monster rolls a 6 and you have 5def you cant use your def correct?The monsters def always works no matter what the roll on dam die ,correct?I'm always a little confused if monster gets to always use his def.value.

Good question. For as long as Iāve played (since 2018) I have truncated, just to keep it a bit more challenging.