How to Lower the River to Reveal the Rocks without Putting a Hole in Your Boat

Toyota’s example has inspired revolutionary changes in the way all manner of goods and services are designed and produced. One of the key features of this new approach is the self-imposition of necessity. Rather than wait for customers or competitors to compel innovation and improvement, In the famous words of Toyota Chief Engineer Ohno, we should ‘lower the river to reveal the rocks’; i.e., deliberately reduce the buffers of time, capacity, inventory and financial contingency that are currently necessary to absorb variation and uncertainty, in order to reveal where the production system needs to be changed. This paper explores the application of Ohno’s advice in the construction industry. Examples of successful implementation are provided, and methods are proposed to reduce the risk of putting a hole in your commercial boat.