There’s the famous old story, about a professor’s analogy for time management, demonstrating it with rocks, pebbles, sand, and water put into a single jar, the jar being your total time spent on earth. Each of the rocks, pebbles, sand and water components representing the things that take up your time. The idea, of course, is that to fit everything into your limited life, you must start filling it with the most meaningful, the “biggest” things first, represented by the biggest rocks. The activities that mean gradually less gets filled in behind the big ideas and dreams, in the order of descending pebble/sand size, etc. And everything fits in a well-balanced life in the priority of importance to you. Any other order and you wouldn’t fit everything in the jar, OR your life, and you’d miss out on the most important “rocks” as activities/passions.
For jiujitsu, this analogy can be used as well for it’s knowledge and the belts within it. Super rough, but imagine those super easy basics, in the beginning, the building blocks of all other knowledge to come, being the big rocks. Rock by rock, each is put into the jar of knowledge until it is “full.” This is followed by the pebbles, the sand, and the water, IN THAT ORDER.
Your first “fill” with the big rocks turns you blue! Boom, you have your first colored belt, that first huge target as the coveted blue. This is a big accomplishment, and you have filled the jar of jiujitsu knowledge with these HUGELY important “rocks”. What you’ve learned were the most important technical chunks of all of jiujitsu.
Of course, the many gaps between the rocks in your knowledge are next to be filled with the pebbles, “filling” the jar once again as you turn purple! The sand, of course, fills the remaining gaps for brown belt til “full” again.
As the water of the black belt knowledge coats every stone and fills every gap, your jar is again full. This is truly beautiful because, like the water in contact with EVERY earlier placed stone regardless of size, the attainment of your knowledge in the pursuit of black belt knowledge should affect every part of every stage of your previous knowledge attainment. It affects every piece, from the sand to the huge “basic” rocks, constantly polishing each of the grains along the way! Your shrimping and bridging gets polished, as well as every movement that incorporates them!
After black belt? Any physicist would tell you how most of the jar STILL holds absolutely nothing. It never ends, and by the time you’ve reached black belt, and most people well before then, you would never want it to.