<table class="mytable">
  <tr>
    <td colspan="2" rowspan="2">abfg</td>
    <td class="t1" rowspan="2">ch</td>
    <td colspan="2">de</td>
  </tr>
  <tr>
    <td>i</td>
    <td class="hideborder">j</td>
  </tr>
  <tr>
    <td class="t1" colspan="5">klmno</td>
  </tr>
  <tr>
    <td colspan="2">pq</td>
    <td class="t1" rowspan="2">rw</td>
    <td>s</td>
    <td rowspan="2">ty</td>
  </tr>
  <tr>
    <td class="hideborder2">u</td>
    <td>v</td>
    <td>x</td>
  </tr>
</table>

body {
	font-family:Verdana, Geneva, sans-serif;
}
h1 {
	text-align:center;
}
.mytable {
	width:500px;
	height:500px;
	margin:auto;
	border:1px solid #000;
	border-spacing:5px;
	table-layout:fixed;
}
.mytable td {
	border:1px solid #000;
}
.t1, #t1 {
	visibility:hidden;
}
td.hideborder {
	border-top:none;
	position:relative;
}
.hideborder:after {
	content:"";
	position:absolute;
	height:6px;
	left:-1px;
	right:-1px;
	top:-6px;
	background:#fff;
	border-left:1px solid #000;
	border-right:1px solid #000;
}
td.hideborder2 {
	border-right:none;
	position:relative;
}
.hideborder2:after {
	content:"";
	position:absolute;
	right:-6px;
	width:6px;
	top:-1px;
	bottom:-1px;
	background:#fff;
	border-top:1px solid #000;
	border-bottom:1px solid #000;
}