New topics:

• king in the middle
• queen ending
• pin
• bishop against pawn
• zugzwang

Elaborating on already introduced material:

• mini plan Opening the position, piece to a better square
• pawn ending The rook's pawn, tempo play, defending
• wrong bishop Winning and drawing positions
• vulnerability Exploiting vulneribility
• defending Defending against threats, a passed pawn, king's attack