Re-raising the issue below:

Why using IEnumerable<string> when you always pass a length 2 array?

Notably, this implementation goes against C# conventions (specifically the IComparer interface) and hence is completely useless for any actual use.

Romanization scheme isn't specified, so the mapping is insufficiently defined (not to mention the mapping is incorrect: see the issue below).

This will also save the effort of defining the entire array in the initial code.

(btw, the arrays should not belong inside the method; they should be static variables)

The mapping provided in the initial code and used by the reference solution is wrong: di (ぢ) and du (づ) are mapped to ji and zu.

Lua translation!

Since Lua strings are byte arrays this exercise is not that simple (maybe 6kyū), but it's very doable.

Duplicate of https://www.codewars.com/kata/prepare-for-the-easter (except for a trivial difference)

there is too much stuff to read about astronomy to solve that kata - most answers are just copy pasted from msdn forum