The Chinese idiom 两肋插刀 is formed by sequentially combining the characters 两 (meaning "two" or "both"), 肋 (meaning "ribs"), 插 (meaning "to insert" or "stab"), and 刀 (meaning "knife") to create a literal image of knives being stabbed into both ribs, which metaphorically conveys the concept of taking great risks or making sacrifices for a friend's sake.