I dont think so phistomefel is required.. i just saw that box 7 needed 1 and 2 outside of the 17 and 25 cages, and 1 cant be in the 19 cage. then i used the same in box 1 and got 2 and 3 out of cages. I started like this

Thanks Madhav Sankaranarayanan for a very fun set. It was a nice challenge to get through all the sudokus. Mathrax took a lot of time for me but had a nice solve path.

Favourites are Product sandwich (9x9) and X Sums (9x9). Hope to see more contests authored by you in future. Well done !

What time does the Episode 4 - Math close for participation?

Hi!

The killer doesn't require the implementation of Phistomefel's ring. The intended beginning involves inclusion-exclusion counting of the boxes 1,4 and 7, and the rest is fairly straightforward killer combinations. Hope this helps.

Nice Puzzles Madhav. Very logical puzzles. Classic Puzzles were very enjoyable. Looking forward to seeing more contests by you.

Thank you everyone for your kind comments! Had a lot of fun setting some of these variants.

Thanks to the 342 participants.

Thanks to Madhav Sankaranarayanan for some innovative puzzles in this round!

Those who missed taking part in this test can still take this test unofficially.

I am not a Math student so did not expect to solve any variant especially since it was authored by a young Math whiz. I am glad I managed to solve both the Mathrax and the 6by6 equation :). I wasted a lot of time on the 9by9 equation sudoku but kept breaking. The classics were very good. I look forward to solving the other variants at leisure.