I see comments suspecting this list is AI-generated. That might be true. But ironically, the practice of "building from scratch" is the best antidote to AI dependency.

Writing from Japan, we call this process "Shugyo" (austere training). A master carpenter spends years learning to sharpen tools, not because it's efficient, but to understand the nature of the steel.

Building your own Redis or Git isn't about the result (which AI can give you instantly). It is about the friction. That friction builds a mental model that no LLM can simulate.

Whether this post is marketing or not, the "Shugyo" itself is valid.