Emerson's fellow countryman Paul Broadhurst, who was one of five players to share the lead after Thursday's opening round, shot a 3-under 67 and is alone in second place at minus-7.
Alessandro Tadini posted a 6-under 64 on Friday and has third at 6-under-par 134.
Emerson bogeyed the fourth hole, but rebounded with a birdie at the next. He collected back-to-back birdies from the seventh to make the turn at 2-under 33.
On the back nine, the 41-year-old caught fire immediately after making the turn. He birdied five of his next six holes from the 10th to get to 8 under for the championship.
Emerson dropped a shot to par at the 16th, but reclaimed sole possession of the lead with a birdie at the par-5 closing hole at Hilversumsche Golf Club.
'I finished ninth here a couple of years ago so I love playing it,' said Emerson, referring to the 2003 event. 'It is an old traditional course, a bit like the Sunningdale of Holland, and I enjoy that.'
Emerson is in the middle of an impressive stretch of golf. He opened with a 63 last week at the Wales Open and that was the first time he bettered his previous best score of 64.
'It is a nice habit to get into, isn't it?' said Emerson. 'You have to drive it well around here because the rough is really penal, but I like playing tree-lined courses because it is easier to pick your targets and see your shots a little bit easier.'
Broadhurst was 1 under par on his round until a bad break at the par-4 11th, a hole he bogeyed on Thursday. His drive disappeared in the rough and he had to return to the tee. The Englishman's second drive hit a tree and came straight down. Broadhurst holed a difficult 15-footer to save double-bogey.
'I managed to hole a good 15-foot putt for double-bogey,' said Broadhurst, who won this season's Open de Portugal. 'That kick-started the round really because it was the sort of kick up the behind that I needed.'
Broadhurst birdied the next four holes after the hiccup at 11.
Tadini tallied six birdies and no bogeys in his 64 on Friday. He tied for fifth last week in Wales and believes the success he experienced there will help him this weekend.
'It was a great experience being in contention for most of the week in Wales and I will be amongst the leaders again tomorrow so I am hopeful of using the experience I had there to help me,' said Tadini. 'If I can continue in the same way over the weekend, I have a good chance.'
Richard Bland (64), Markus Brier (68) and Steven O'Hara (65) and 2003 winner and local favorite Maarten Lafeber (67) are knotted in fourth place at 5-under-par 135.
First-round co-leaders Gonzalo Fernandez-Castano and Guido Van der Valk each carded rounds of even-par 70 and fell into a tie for eighth place. Miguel Angel Martin and Andrew Oldcorn both posted 67s on Friday and joined Fernandez-Castano and Van der Valk at minus-4.
Adam Groom, the fourth of five first-round co-leaders, shot a 1-over 71 and dropped into a tie for 12th at 3-under-par 137, along with defending champion David Lynn.
Henrik Nystrom, the final member of the logjam that occupied first on Thursday, struggled to a 2-over 72 and is tied for 18th place at 2-under- par 138.
The 36-hole cut fell at 4-over-par 144 and 82 players advanced to the weekend.