Pronunciation of 四段 (karate level)

[two_heads_talking]

Maybe its both youdan and yondan, just as it happens with nihon and nippon which are both correct readings of the sun and book kanji.

while you might be correct, the difference between nihon and nippon is pretty much the same as yahadi and yappadi or yahashi and yappashi.. not quite so much a reading but a dialectal difference.

Chris or some others can correct me if I have t his wrong, but I believe Nippon was the pre-WWII usage and while still used for political or other 'formal' occasions, nihon is the post-WWII usage and the most commonly and normally used ..