American forces hit two Iranian rocket launchers on Larak Island on Sunday. CENTCOM said Revolutionary Guard crews had been observed getting ready to fire rockets carrying sea mines into the strait, and that the launchers were destroyed before they could shoot. Iranian state media reported dead and wounded. The Guards promised punishment for the aggressor. Brent for November went through $90 and WTI moved up near $86 as the news landed in a market that had spent most of last week pricing in a deal.

Of all the weapons in Iran’s arsenal for threatening the Strait of Hormuz, the naval mine is the one that demands the most serious attention. It is not the most dramatic option — no missile streaking toward a supertanker makes for better television — but it is the most operationally credible, the hardest to counter, and the one with the longest historical track record of actually disrupting Gulf shipping.

Understanding why requires understanding what mines do that other weapons do not.

The headline weapons of Iranian maritime strategy are missiles and fast boats. The actual weapon, the one that has done the most damage at the lowest cost across four decades, is the sea mine. Mines are unglamorous, undermarketed, and operationally devastating. Any serious analysis of a Hormuz contingency starts with them.

Iran’s mine inventory is large and varied. Estimates run to several thousand devices, ranging from refurbished Soviet contact mines to indigenous influence mines triggered by acoustic, magnetic, or pressure signatures. Some are tethered. Some are bottom-laid. Some are smart enough to count ship signatures and ignore the first several passes before activating. The technological floor is low. The technological ceiling is high enough to challenge even modern minesweeping.