source: Šachová skladba
source-id: 56/4193
date: 1997
algebraic: 
  white: [Kb7, Qh4, Be6, Pf4]
  black: [Kd6, Pc4]
stipulation: "#4"
solution: |
  "1.f4-f5 ! zugzwang.
        1...c4-c3 
            2.Qh4-f6 threat:
                    3.Be6-b3 + 
                        3...Kd6-d7 
                            4.Bb3-a4 # 
                        3...Kd6-c5 
                            4.Qf6-b6 # 
                2...Kd6-c5 
                    3.Qf6*c3 + 
                        3...Kc5-b5 
                            4.Be6-d7 # 
                        3...Kc5-d6 
                            4.Qc3-c7 # 
        1...Kd6-e5 
            2.Kb7-c6 threat:
                    3.Kc6-c5 threat:
                            4.Qh4-d4 # 
        1...Kd6-c5 
            2.Qh4*c4 + 
                2...Kc5-d6 
                    3.Qc4-c7 #"