Fortune #30

In a published tale, a blacksmith lacks enough nails to secure a horse's shoes. The groom urges him to hurry because the king is waiting. They let a small step go unfinished.

During battle, a shoe comes loose and the tale links defeat to the missing nail. This is a moral story, not evidence that a real battle turned on one nail.

When solving a problem, you can memorize the shape of a solution and skip why one step works because it looks minor. A new question may change the conditions that made that step valid.

Write a reason beside two steps you usually copy. If you cannot explain one, pause there before doing more examples. Understanding the small link keeps the method usable when the question changes.