<div class='user_solution'><span style="text-align:justify;display:block;" class="MsoNormal"><b>1.e7! </b></span> <span style="text-align:justify;display:block;" class="MsoNormal"><b> </b></span> <span style="text-align:justify;display:block;" class="MsoNormal"><b>1…Nxe7 2.Nab5+! Ke6 3.Nc7+ Kf6 </b></span> <span style="text-align:justify;display:block;" class="MsoNormal">no<span>  </span>3...Kd6? 4.N3b5# </span> <span style="text-align:justify;display:block;" class="MsoNormal"> </span> <span style="text-align:justify;display:block;" class="MsoNormal"><b>4.Ne8+ Ke6 5.f5+! </b>for autoobstruction <b>5...Nhxf5 </b></span> <span style="text-align:justify;display:block;" class="MsoNormal">no<span>  </span>5...Nexf5? 6.Bd5# </span> <span style="text-align:justify;display:block;" class="MsoNormal"> </span> <span style="text-align:justify;display:block;" class="MsoNormal"><b>6.Bd5+! </b>for autoobstruction <b>6...Nxd5 7.Ne4 </b>double threat in c5 and g5 <b>7...Qc1 8.Rd2 </b><b><span style="color: red;">(1)</span></b> <b>8...Qg1 </b></span> <span style="text-align:justify;display:block;" class="MsoNormal">no<span>  </span>8...Qxd2? 9.Nxc5# </span> <span style="text-align:justify;display:block;" class="MsoNormal"> </span> <span style="text-align:justify;display:block;" class="MsoNormal"><b>9.Rf2 </b><b><span style="color: red;">(2)</span></b> <b>9...Qc1 </b></span> <span style="text-align:justify;display:block;" class="MsoNormal">no<span>  </span>9...Qxf2? 10.Nxg5# </span> <span style="text-align:justify;display:block;" class="MsoNormal">no<span>  </span>9...Nf6? 10.Nc7# </span> <span style="text-align:justify;display:block;" class="MsoNormal"> </span> <span style="text-align:justify;display:block;" class="MsoNormal"><b>10.Rf3 Qg1 </b></span> <span style="text-align:justify;display:block;" class="MsoNormal">no<span>  </span>10...b2? 11.Rc3+- mate in 14 moves</span> <span style="text-align:justify;display:block;" class="MsoNormal"> </span> <span style="text-align:justify;display:block;" class="MsoNormal"><b>11.Rg3 </b><b><span style="color: red;">(3)</span></b> <b>11...Qc1 12.Rc3 </b><b><span style="color: red;">(4)</span></b> <b>12...Qg1 13.Rxc5 b2 14.Rc6+ Nd6 15.Ng7</b><span># </span><b>mate ideal</b> </span> <span style="text-align:justify;display:block;" class="MsoNormal"> </span> <span style="text-align:justify;display:block;" class="MsoNormal"><b>Four interferences with the rook.. See (1) (2) (3) and (4) <span><span> </span></span></b></span></div>