If you study any modern Japanese martial art, you are no doubt familiar with the concept of "do." It's most often translated as "way" or "path," which makes for a very handy and versatile metaphor for the long, wonderful journey that is budo.
If, then, the study of a martial art (or really anything) can be likened to a path, what does that path actually look like? To me, it takes on different forms as you progress.
A paved street
When you first start your study of an art, and for some time afterward, the path will probably look like a paved street. That road has been paved by the many who have come before you, who have traveled this exact path a hundred thousand times. It's a solid foundation, and it's objective is firm.
There are all kinds of signs and maps to help you along your way, to guide you in the right direction, also designed by those who arrived long before you. Failure to follow that guidance will likely get you lost very quickly.
There are clearly painted guidelines to keep you from deviating off course. There are strict laws, partly designed for your protection and the safety of others, but also to help the process run as smoothly as possible, not just for you but all the others traveling alongside you (and there will be many).
The beginner's path tends to be straight and direct with little variation. It will get you from A to B, all you have to do is follow it.
A dirt road
After years of study, you may find the road you have been traveling has gradually changed to something more akin to a dirt road.
Now the path is less sure, less defined. Fewer people have come this far, so true guidance can come from only the most experienced travelers.
And you may also notice that there are a number of different paths, not just your own. Not better or worse, just different. As O Sensei once wrote, "There are many paths leading to the top of Mount Fuji, but there is only one summit—love."
There are fewer markers, it's not as straight, and there are more turns to choose from, so the likelihood of wandering off into unfamiliar areas increases. That can be a good thing or a bad thing: you could discover something new and enlightening, or you could get distracted and caught up in a direction that leads nowhere.
The responsibility of finding your way is less reliant on others as it was in the beginning. The journey is less about following and more about discovering.
The path you make
After even more time and training has passed, the path you take may very well be one you make yourself.
There could be no discernible path at all, just a vast, ever-changing wilderness. It may then fall upon you to blaze new trails. You will run into obstacles: some you can clear, other you'll just have to go around. You will occasionally have to double back the way you came and try something else. It's both arduous and wondrous, frustrating and exhilarating. It can certainly get lonely.
It also becomes your responsibility, if you wish not to end up alone, to look back and reinforce the road you've traveled and make it sustainable, to make it available for those who come after you. You yourself become the map, the traffic light, the painted lines that guide the newer students.
You have gone from traveller, to trail blazer, to caretaker. Ultimately, you will be all of these. The road is what lays ahead, what lays behind, and what lays beneath your feet.
Indeed, the world itself is your path, "heaven is right where you are standing." Because, as O Sensei once put it, "the Great Path is really No Path."