Thanks for your solution, hint and "text":-)... Corrected the description. I've forgotten that i published some katas long long time ago;-)... Perhaps you will find some more intersting ones in my (c#-) list and maybe with a better description:-)...

Like Suitecake I found the description confusing.

Having solved by guesswork based on the test cases, how about:

"For every character in string a swap the casing of every occurance of the same character in string b. Then do the same casing swap with the inputs reversed. Return a single string consisting of the changed version of a followed by the changed version of b."

Yes, here i agree... Perhaps someone can give a better description - if it should be necessary for finding a solution. But should be no dissertation - i normally look at the examples and testcases without intensiv reading of (long) descriptions. Last but not least, codewars is fun, spare time and not job, so take it easy... not everything has to be professional, descriptions included... sometimes descriptions are not in best form, nevertheless a good developer can solve it.

That's no issue and it's not correct too. Two of the four first testcases include uppercase letters (by the way the first testcases don't need to handle every possibility). Generally this kata is simple, too simple to say more and here perhaps the description is the "hardest part";-). For better understanding there are easy examples too. So thanks for your suggestion, i'm sure you are able to solve it (next time);-)...