solution: |
  "1...Kxd3[a] 2.Qb3#[A]
  1...Kxf3[b] 2.Qh3#[B]
  "1. d4? [2. Qb3#]
  1. ... Kxf3! 
  
  1.Qe5? zz
     1...Kxd3[a] 2.Qc3#[C]
     1...Kxf3[b] 2.Qg3#[D]
  but 1...e6!
  1. f4? [2. Qh3#]
  1. ... Kxd3! 
  
  1.Qb6+?
     1...Kxd3[a] 2.Qb3#[A]
  but 1...Kxf3[b]!
  1. Qb3? ad lib 2. d4#
  1. ... Kxf3! 
  
  1.Qh6+?
     1...Kxf3[b] 2.Qh3#[B]
  but 1...Kxd3[a]!
  1. Qh3? ad lib 2. f4#
  1. ... Kxd3! 
  
  1.Qh3[B]? (2.f4#[E])
  but 1...Kxd3[a]!
  1. Qe5? waiting
  1. ... Kxd3 2. Qc3#
  1. ... Kxf3 2. Qg3#
  1. ... e6! 
  
  1.Qb3[A]? (2.d4#[F])
  but 1...Kxf3[b]!
  
  1.f4[E]? (2.Qh3#[B])
  but 1...Kxd3[a]!
  
  1.d4[F]? (2.Qb3#[A])
  but 1...Kxf3[b]!
  
  
  
  1.e5! zz
     1...Kxd3[a] 2.Qb3#[A]
     1...Kxf3[b] 2.Qh3#[B]"
  1. e5! waiting
  1. ... Kxd3 2. Qb3#
  1. ... Kxf3 2. Qh3#"
keywords: 
  - Changed mates
  - Threat reversal
  - Urania
  - Banny
  - Hannelius
  - Block