Sid Meier's Civilization: The Board Game

You may build a city during your Start of Turn if you have a scout in the square and the square is non-water, fully revealed (eight adjacent squares), not adjacent to a hut/village or enemy figure, and at least three squares from any other city center; you sacrifice the scout and place the city marker (the city center never produces yields). (p.13)

You collect trade during the Trade Phase by adding all trade symbols in your cities’ outskirts to your trade dial (trade is pooled and can be saved), while production is a per-city resource spent during City Management and cannot be saved; trade and production are distinct and convertible only by paying trade to rush production. (pp.12, 14–15)

Scouts cannot enter hut or village squares; an army that enters a hut peacefully takes the hut for its owner, while entering a village triggers a barbarian defense (a battle vs. barbarians) with post-battle rewards if you win. (p.20)

Each side draws a battle hand equal to its battle hand size (base 3 plus +2 per additional friendly army in the square, bonuses from government or defending a city/capital), then players alternately play unit cards into fronts where units deal wounds equal to their strength (wounded units can still deal full damage), with trumps dealing damage first; surviving unit totals plus combat bonuses determine the winner. (pp.23–25)

To research you must meet the trade threshold for the tech level (I=6, +5 per level thereafter) and have a legal spot in your tech pyramid; researching normally spends all your trade but you keep 1 trade per coin you possess (coins let you retain trade when researching). (pp.20–21, 26)

A square in a city's outskirts that contains any enemy figures is blockaded and produces no trade, production, culture, coins, or resources for that city; however, a scout in a square may ‘send’ that square to one of its owner’s cities for the turn, making the square count as that city’s outskirts and negating the blockade's effect for the sending player's city. (pp.14, 26–27)