No.637 Peter Harris (South Africa) 
Original Problems, Julia’s Fairies – 2014 (III): September – December →Previous ; →Next ; →List 2014(III) Please send your original fairy problems to: julia@juliasfairies.com 
No.637 by Peter Harris – Interesting thematic mates to the both Royal Pieces – rR in (a) and rR+rB in (b)! (JV)
Definitions:
Sentinels Pion Advers: When a piece (not a Pawn) moves, a Pawn of the colour of the opposite side appears on the vacated square if it is not on the first or the last rank, and if there are less than 8 Pawns of that colour on the board.
Royal piece: Piece that executes a function of the King on the board.
No.637 Peter Harris 
Solutions: (click to show/hide) 
white royal re7
black royal bh1
neutral qd3
hs#3,5 b) h##3,5 (1+1+1n) 

I never know how many JF visitors are interested in my problems.
For those who are:
This 537 problem was one of many I made.
The hs solution could be more thematic. The Black move giving mate is not the Black Royal piece. [But I became enamoured with the Qh6# sequence of moves]. A 2 solution version, one giving the 537 mate by the Q, the other by the rbB is:
rwRf7, rbBh1, nQd3 hs#3.5 sentinelles pionadvers [1+1+1] 2 solutions. [This also gives a 1solution h##3.5].
The following is a 2 solution h##3 problem:
rwRd1, rbBa8, nQa3 h##3 sentinelles pionadvers [1+1+1] 2 solutions. [This is 3 not 3.5 and Black is in check].
Lastly, I did think of sending Julia the following which is prettier than 537 and is much simpler being 3 long and with Sentinelles not Pionadvers:
rwRc5, rbBe4, nQd8 sentinelles (a) hs#3 (b) h##3 [1+1+1].
The extra half move makes a big difference with Difficulty – so perhaps I should have sent this instead.
I also made h## problems with other Royal pieces including 2 R – after the last move the Rs were side by side mating each other.