<span class=" f4">1.Bg2? </span><span class=" f4">threat</span><span class=" f4">: 2.Qe4+ (A) Kc5 3.Qb4# (B)  (MM)</span><span class=" f4"><br />1...Kc4 2.Qb4+ (B) Kd3 (A) 3.Qe4# (A)  (MM)</span><span class=" f4"><br />    </span><span class=" f4">but 1...a5</span><span class=" f4">!</span><span class=" f4"><br /></span><span class=" f4"><br />   </span><span class=" f4">1.Ba6! </span><span class=" f4">zugzwang</span><span class=" f4">.</span><span class=" f4"><br />   </span><span class=" f4">1...K*d5</span><span class=" f4"> 2.Bg3 </span><span class=" f4">zugzwang</span><span class=" f4">.</span><span class=" f4"><br />   </span><span class=" f4">2...Kc6</span><span class=" f4"> 3.Qd6#  (MM)</span><span class=" f4"><br />   2...Kd4 3.Qe5#  (MM)</span>