5 archers against 2 spears is a bit risky and 3 archers is really not enough. Offa made a great tool that can calculate the odds of taking a city, download it and play with it a bit. My advise is to always have enough units to take the city with 90% chance. That means 7-8 archers against 2 spears IIRC.STUPID RNG!!! I had 5 archers lined up against 3 spears in their capital with no defensive bonuses and I failed to take it! Then I had 3 archers vs 2 spears against a cultured town, and they failed too! This game is no longer winnable, as Korea has swords.