In combat, expect weapons to make moderate levels of contact with all parts of your body but your head and groin. While hands are not a valid target, they are likely to be struck on occasion and striking a hand is not considered a safety violation the way striking the head or the groin is. Note that while strikes to the head and groin are not permitted, they may occasionally happen by accident; if you cannot risk suffering such a strike at all, you should consider being a non-combatant.
You may strike and be struck from any angle. There are no special rules for attacking someone from behind.
"Tests of strength" should be avoided. If you find your weapon or shield locked up against an opponent's weapon or shield, the correct action is to disengage, not have a shoving match. A good rule of thumb is that if your weapons/shields have been in nonstop contact for a three count, you are probably engaging in a test of strength and should both disengage.
You should not grab or otherwise hold on to any opponent's weapon, shield, gear, or body during combat. You may grab allies (or place a hand on their shoulder and call “Carrying!”) for the purposes of doing things like dragging a wounded ally to safety. Incidental contact is likely to happen, but you should not engage in wrestling matches during combat or try to rip someone's weapon or shield out of their hands.
You should maintain control of your weapon and shield at all times. If you drop an item for any reason, you should pick it up as quickly as possible to avoid creating a tripping hazard. If you drop an item in the midst of a chaotic melee it is appropriate to call "hold" while you retrieve the item. This does not apply to thrown weapons.
Melee weapons should have a core (e.g. kite spar or fiberglass), a padded striking surface, and be in generally good condition (e.g., core not visible, not bent in a way that indicates imminent breakage, no tears in the construction material, etc.). Weapons by well-reputed LARP weapon makers are generally going to be acceptable. Many home-made weapons will be as well.
Entangling weapons such as nets are not allowed.
You may wield any melee weapon that 1) is deemed to be safe by the safety team and 2) you can demonstrate you can use safely and within Project Valhalla's calibration standards. Do not be the reason that weapon standards have to become more detailed.
Foam dart blasters must fire at 130 fps or below, and must only fire one projectile per pull of the trigger. Additionally, these weapons must not be battery powered or HPA (compressed air). The term “foam dart blasters” refers to toy guns, bows, etc that shoot any of the following: full length foam darts, half darts, Nerf Rival rounds. Gel rounds, discs and other forms of ammunition are not permitted. (see: Combat).
Thrown weapons may either be coreless of any size or cored with no portion of the weapon being small enough to fit into an eye socket. They work just like arrows. If your thrown weapon is not substantial enough to be felt when it connects and it hits someone in the back and they don't notice it, that's a you problem; get beefier throwies. In-game, it hit at a glancing angle and didn't harm them.
Entangling weapons such as bolas are not allowed.
Shields should be light enough and have sufficiently padded edges to not harm any players who accidentally come into contact with them or any weapons that are deflected by them.
Shield bashing is not permitted.
Armor you wear must allow you adequate visibility and range of motion to fight safely, must not pose a safety risk to people or weapons (e.g., no sharp metal spikes), and you must be able to feel hits of an appropriate calibration through your armor. Armor should be inspected by the safety team just as weapons are.