Here is the current Tenhou advancement chart:

The bottom ranking (at the top of the chart) is 'rookie' - then it advances through the semi-standard martial arts ranking of 9級 (9kyu - lowest amateur rank) up to 1級 (1kyu-highest amateur rank) and then to the dan (expert?) ranking from 初段 (1dan or 'being dan') up to 十段 (10dan) and then there is one more row under that... not sure what that is. Is that even higher ranked than 10dan?
As you can see the table is very forgiving during most of the kyu rankings. You gain points for winning... and generally don't lose points for finishing last. So it's just a matter of time before you march up through those lower ranks.
I'm guessing the second to last column is the # of players in the Tenhou database with that ranking. Interesting that it gets less and less as you head towards 1kyu and then bumps back up as you hit the dan rankings... I guess once you get down to 3 or 2 kyu you just push on to the dan levels where you maybe stagnate a bit.
What is the last column? The average 'rating' for players of that rank?
And does anyone know what the little black down-triangle/arrow is on those required points at higher levels? Does that mean you have to win/place in some sort of ranked events to advance?
As an aside, I assume that once you hit the 1dan or better area are allowed access to that higher-ranked lobby on Tenhou. I'm guessing that at 4dan and better you get access to the final higher-ranked lobby. I also assume that when you get down to levels where you can lose points, you can drop levels if you do really poorly.
This became interesting to me becase I just got my 5級 ranking on Tenhou this week!
