We are interested in situations where Black can double check White in a two move problem. Since a King in double check must move, we see that such a double check by Black must be met by a royal battery. We will explore this situation in depth in this post. This was one of my first research experiences in in the theory of chess problems. We also refer readers to the July issue of StrateGems in 2016 (SG 75) for my article.
The above problems give you a typical way for Black to double check in a two mover: Black fires a battery that leaves the rear battery piece pinned while the front piece is captured by the wK which at the same time fires its own battery. I set out to investigate the following question: is it possible for Black to double check with out the checking pieces being captured? The answer is yes and here are some examples.
In my investigation I noticed that I could not find an example in which a bR and a bB delivered the double check without capture. The geometry will not allow for a R+B or B+R battery to be fired with the pinning that is required. However, there is another way! It turns out that it is possible for a bR and bB to double check without either piece moving!
On the side I like to dabble in chess problem composition. I am mostly interested in two and three move direct mates. I hope to convey the beauty and logic of chess problems with this blog. In the entries are some of my favorite problems and my own problems. Before looking at the problems I suggest reading this introduction to the chess problem world by the British Chess Problem Society. Also, here is a list of terminology and themes. Here is a link to my problems on yacpdb.
1. "Choose wisely" The Problemist Supplement, Sept. 2016
2. "Double checking white in a two mover" StrateGems July 2016
3. "Double check without capture" The Problemist Supplement, January 2018
4. "The disappearing Nowotny: Part I" The Problemist Supplement, March 2018
5. "The disappearing Nowotny: Part II" The Problemist Supplement, May 2018
6. "The disappearing Nowotny: Part III" The Problemist Supplement, July 2018
7. "Castling with half-battery and Fleck themes" StrateGems, July 2018
8. "The Baku Nowotny" StrateGems, January 2019
9. "The Romanian Nowotny with Fleck" The Problemist, March 2019
10. "Mirror Image" The Problemist Supplement, May 2019
11. "White King in Check" Problemas, July 2019
12. "A Simple Mechanism", StrateGems, July 2019
13. "Miniatures with castling and (partial) Fleck" Problemist Supplement, September 2019
14. "Taking the Straitjacket off the Fleck" The Problemist Supplement, November 2019
15. "Unforced threats" The Problemist Supplement, May 2020
16. "Ojanen in Miniature" The Problemist Supplement, May 2020
17. "Developments in the Finnish Nowotny" The Problemist, July 2020