The Five Elements
Five phases of one process — not five substances. Everything in a BaZi chart is read as some mix of these, and as how they feed and check each other.
The Generating cycle
木→火→土→金→水
Wood feeds Fire, Fire makes Earth, Earth bears Metal, Metal gathers Water, Water feeds Wood — a closed ring with no beginning. Generating is not free: the mother spends herself on the child. An element that generates too much drains, and one that is generated too much gets flooded. This is why a reading rarely says "you need more of X" without asking what would have to give.
The Controlling cycle
木→土→水→火→金
Wood parts Earth, Earth dams Water, Water quenches Fire, Fire melts Metal, Metal cuts Wood — the five-pointed star inside the ring. Control is not hostility; it is the brake that keeps the ring from running away. Balanced control looks like discipline. Too much and the controlled element is crushed (克太过); too little and it runs wild. Overwhelm the controller instead and it rebounds — 反侮, the axe that shatters on the tree.