Go see for yourself (Genchi Genbutsu)
This is one of my favourite Toyota Way practices. We're often so enraptured by our designs, ideas and plans that we fail to take reality into account. Genchi Genbutsu tells us to go out there and see the world for ourselves and not to rely on reports that distance us from reality.
Here's an instance where I applied this principle.
I was asked to develop a system that would support the workflow for a mail handling facility. Process flows had been designed and I "just" had to implement the system to implement that flow.
Part of the workflow looked like this.
Pretty simple: one guy verifies if the customer's documents are all filled in, in triplicate. If the documents look ok, the second guy has to weigh the mail. Nothing too complicated...
When we were going over the process, I proposed to Genchi Genbutsu. We would all act like a pallet of mail and go through the process ourselves, to really get to know the process.
When we came to that part of the process, we noticed that these two guys were separated by a big wall. No way to pass the customer's documents through there. To get the documents from one guy to the next, they had to walk around the back, through two doors, 50m each way. To pass a document! Clearly, a case of severe "MUDA"!
When we asked the people there, they said "Yeah, we've been asking to put a door into that wall for the past five years!". Clearly, no-one had done a Genchi Genbutsu before!
And what happened next? The wall is still there; there's still no door. We changed the process: now the documents go directly to the second guy...