visual knowledge (visual model)
Examples of visual knowledge from Allen's original training materials (see the first reference below):
Note that Allen also used the term "visible knowledge" interchangeably with "visual knowledge", though the latter is more accurate to his meaning.
The only visual modeling software designed to enable truly reusable knowledge and LAMDA practices can be found here.
The first uses of "visual knowledge" and "LAMDA" "model" terms were in training manuals that Allen Ward was using in his consulting practice in the early 2000's. One of those was posthumously published as the bulk of this book:
A.C. Ward, D.P. Oosterwal, D.K. Sobek II, Visible knowledge for flawless design: The secret behind lean product development, Productivity Press, Taylor and Francis Group, 2018. (click here for more on that book)
The most extensive treatment of those visual modeling practices is in this book:
P.W. Cloft, M.N. Kennedy, and B.M. Kennedy, Success is Assured: Satisfy your customers on time and on budget by optimizing decisions collaboratively using reusable visual models, Productivity Press, Taylor and Francis Group, 2019. (see SuccessIsAssured.com)
Origins of the Term: the generic terms "knowledge", "model", "visual", and "visualization" long pre-date this specific "visual knowledge" / "visual model" definition which was introduced by Allen Ward in the late 1990's to describe Toyota practices. Some specific discussion can be seen in this video by Dr. Allen Ward; and his training materials on "Visual Knowledge for Flawless Design" was published posthumously as a book by the same name in 2018 (more on that here).
Definition: one of a collection of engineering practices that Dr. Allen Ward observed at Toyota. Allen asserted in his training materials in the early 2000's, "Visual knowledge is the primary tool that enables Toyota to design entire automobiles in 12 months [...] without building and testing prototypes." (see first reference below, page 2). Allen noted that the visual cortex constitutes a significant portion of our brains and engaging it can have both collaborative and innovative advantages; when collaborating, visual knowledge helps ensure accurate communication. The "visual model" synonym ties to the “M” in the ‘LAMDA’ mnemonic that Allen coined for Toyota’s key learning behaviors. Causal / Decision Maps (used to map the design space) and Trade-Off Charts (used to show the limits of the design space) are two particularly important visual models, but any visual such as free body diagrams, circuit diagrams, CAD models, or even simple alternatives matrices or other tabular data would also be included. Visual models are often organized into k-briefs to support LAMDA discussions.
Origins of the Practice: the use of visualizations certainly dates back to Egyptian hieroglyphs and earlier. Even the use of visualizations specifically for engineering or scientific purposes dates back to Greek geometry and earlier. Leonardo da Vinci certainly made tremendous advances in scientific modeling and visualization over 500 years ago. However, the specific practices that we are referring to here, of avoiding engineering discussions without creating visual models to facilitate that collaboration, were developed over time in the continuous improvement of the Toyota Product Development System from the 1950's through the 1990's when observed by Allen Ward's team.