URI-ST
Unlimited Resource Influx - Solution to TradingStep 0: No traps, no cages, no marksdwarves, no magma.
Step 1: Build drawbridge over a channel.
Step 2: Dig a winding hallway.
Step 3: Build another drawbridge.
Step 4: And then another winding hallway.
Step 5: Dig out small barracks, to serve as a last ambush and thief detector.
Step 6: Assign Urist McSpeardwarf and Urist McAxedwarf to the barracks.
Step 7: Let them train.
Step 8: If there's an ambush or a siege and they aren't legendary Fighters, Shield Users, Axe- and Speardwarf respectively, rise the bridges and keep them that way for a season or two.
Step 9: If they are, see how's their Armour User skill, and what kind of armour are they wearing. Ideally, it should be iron or cotton candy. Same with weapons, except here steel is ok.
Step 10: Now that our two psychopaths are ready and able, lower the bridges.
Step 11: Take your time, let the goblins admire the hallway. Rise and lower the bridges if you feel like watching flying gobs.
Step 12: Once most of the siege is inside, rise the outer bridge.
Step 13: Order the Psychos4Life to move to the other end of the hallway, so that they meet our now trapped guests.
Step 14: Poor goblins.
Step 15: Write down how many invaders they killed each, compare to previous sieges. Have a beer in celebration if the kill stats were particularly impressive, and read some of the combat log.
Works well usually, except when it doesn't, and one of the trolls or elite gobs gets a lucky hit.
Fun for me either way