Ukraine has launched a big drone campaign against Russian shipping in the Sea of Azov, a rare win that's squeezing Russia's oil money and its grip on Crimea.

• Since early July, Ukraine says it has hit over 100 Russian vessels in the Azov, mostly the small tankers that ferry oil to bigger ships for export.
• The goal isn't to sink them but to disable them, so Russia sells oil slower and has to pay to repair a growing pile of damaged ships.
• Russia's economy is already hurting — fuel shortages, rising prices, falling oil output, and growth close to stalling — so lost export income stings more.
• Crimea is the real target: strikes on ferries, fuel depots, and ships are cutting off supplies, and the region declared an emergency over power and fuel shortages.
• Ukraine still can't retake Crimea by force — it's heavily mined and fortified — so this is about making Russian rule there look weak and costly.

Outlook: Ukraine plans to keep hammering Russian ships and Crimea's supply lines, though the recent firing of its drone-focused defense minister raises questions about momentum.