You can only keep ONE tool as a value investor. Everything else disappears. What do you choose?

Let’s say tomorrow every investing tool you use vanishes. You’re allowed to keep just **one** thing. What survives? For me, it would probably be the 10-K. If I can read the annual report and understand the business, risks, and capital allocation, I feel like I can rebuild everything else from there. But I’m curious what others would pick. Is it: * EDGAR? * Excel? * A specific paid platform? * Your own notes? * Something totally different? If you had to strip it down to the absolute core of your process — what’s the one tool you refuse to give up?