Link: https://marcoskwkm.github.io/riichi
So far this only has a tool to help you practice calculating hand scores given han and fu values. I will probably add more stuff as I feel like it.
URL: https://marcoskwkm.github.io/riichi#/score-table
Simple table of scores to be used for reference. Score follow WRC rules as of 2022.
URL: https://marcoskwkm.github.io/riichi#/score-calc
The box gives you the information you need to calculate the hand score. Type the hand payments in the input box in the form [non-dealer payment]/[dealer payment] in case of non-dealer tsumo, or in the form [player payment] otherwise. For example, for a 1 han 30 fu non-dealer ron the answer is 1000, and for 3 han 25 fu non-dealer tsumo the answer is 800/1600.
Type in your answer and press enter. If your answer is right you'll be given another prompt. Otherwise, you can try again. In case you get it wrong the expected answer will be printed in the developer console (too lazy to actually put it on the interface), so you can double check if your memory/calculation was correct.