I discovered Lean (but we didn’t call it Lean then) and Theory of Constraints at the same time, when I joined a Yamaha Corp. subsidiary in 1989. Even so I gathered more experience with Lean, I used ToC principles and rules when relevant. Six Sigma came later but without surprise as I had been extensively trained about Statistical Process Control (SPC) long before Six Sigma gave it a new shine.
I used TLS without knowing it and came across concept and acronym only in the 2010s while reading Reza PIRASTEH and Kimberly FARAH’s paper “The top elements of TOC, lean, and six sigma(TLS) make beautiful music together” ( May 2006, APICS Magazine) and Bob SPROULL’s “The Ultimate Improvement Cycle” (CRC Press, 2009).
My “discovery” of TLS was nothing more than conceptualization and confirmation of what I have experienced by myself and found natural: using what the three components of TLS had to offer as a powerful synergy.
Introduction to TLS
This slide show will give you an introduction to TLS.