There’s a moment in The Book of Five Rings where Musashi makes it painfully clear: a warrior who stops sharpening his blade has already lost. Not in battle, but in mindset. And honestly, software teams fall into that trap all the time.

We cling to old tools, old patterns, old decisions—because they once worked, because we invested in them, because changing feels like admitting we were wrong. That’s when the sunk cost fallacy sneaks in wearing a samurai’s armor, whispering, “You’ve trained this way for years; don’t turn back now.”

But Musashi didn’t win by repeating yesterday’s moves. He won because he adapted relentlessly. He questioned everything. He sharpened continuously—skills, strategy, awareness. Nothing was sacred except improvement.

In development, the moment we hesitate to re-evaluate a system “because of all the effort already spent,” we dull our edge. Legacy code becomes a shrine no one dares to disturb. Inefficient processes survive out of habit. Innovation stalls, and the product suffers.

The better path? Musashi’s path. Look at the work with clear eyes. Let go of the emotional attachment to hours already burned. If the architecture needs to change, change it. If a tool is slowing you down, replace it. If your approach no longer fits the terrain, shift your stance.

Continuous sharpening means refusing to be ruled by past investment. It means choosing effectiveness over ego—every single time.

A sharp blade isn’t the result of loyalty to the past. It’s the result of fearless, ongoing refinement.