Though different due to the use of clones, the Iron Mountain Leaning is a taijutsu move that is a technique commonly used in Chinese martial arts, mainly derived from Bajiquan/Hakkyokuken (lit. Eight Extremes Fist) and is pronounced as the Tieshankao ("Tee-uh-shah-n-kah-oh") in pinyin. The attack through its Japanese reading is often adapted into video games and is often portrayed as a turning back/shoulder-lean through explosive force. More info can be seen about it here.
However, the Tetsuzankō itself is derived off of the Tieshankao/Tenzankō (貼山靠, lit. Applying Mountain Lean) through the first character being changed.