This Article takes an in-depth look at Article 36 of the First Additional Protocol to the Geneva Conventions, and asserts that its phrase “in some or all circumstances” requires states parties to review the legality of their weapons and methods of warfare in light of both normal and expected uses. This would include use in the context of caves and bunkers, as such warfare has become more common in the past few years. Part I of this Article provides the theoretical framework for international humanitarian law (IHL) and contextualism. Part II’s survey of state practices suggests Article 36 legal reviews currently do not consider context as they should. Part III demonstrates how some weapons’ legality may shift depending on the setting in which they are used, thus emphasizing the importance of context in legal reviews. Indeed, the confined, opaque space of caves and bunkers makes the weapons and methods used there prone to violate the IHL principles of discrimination and humanity, as well as the IHL prohibitions of poisoning and asphyxiation. Contextualized legal reviews are necessary to ensure that both the spirit and letter of IHL prevail.