18 competitors, including defending champion Karrie Webb, were still waiting to tee off as Koch made the turn.
Koch, sporting pigtails, shot 32 on the front nine this morning catapulting herself into the lead early on at the first major of the year. Birdies on the first and second holes insured a good start at the first major of the year while an eagle on the par-4 sixth gave her the edge she needed to gain control of the lead heading into the back nine.
She was 4-under-par through the 10th with Dottie Pepper and fellow Swede Liselotte Neumann just one stroke off the lead.
Pepper - the only player to have participated on every Solheim Cup team - got off to a rocky start with birdie on the second hole followed by bogey-bogey on the next two holes.
A hole in one at the fifth turned her game around. Pepper went on to make birdie on the next two holes and finished the front side in 33 stokes. She was three under through the 12th after making birdie on the par-5 11th and bogey on the par-4 12th.
Amateur Lorena Ochoa was 1-under-par through the 10th. Ochoa, a native of Mexico, carded her first birdie on the par-5 second hole of the day.
Meg Mallon took six full weeks off and is now back in action and looking to complete the career Grand Slam. A win this week for her wound make the Grand Slam complete. Mallon was 2-under-par through the 11th. She made birdies on number two and the par-4 10th.
Fatigue is evident in Annika Sorenstams game today. Sorenstam was at even par through the 11th after making two birdies on the front side and bogey on the par-3 eighth and again on the 10th.
The Wongluekiet twins tee off at 12PM and 12:10PM respectively. Webb tees off at 11:50AM.