The B9129 is a link road which sort of cuts the corner between the A914 near Kingskettle and the A92 by Ladybank. It isn't exactly a short cut, due to the speed limits and junctions passing through the villages, but for those communities it is an important road. The road was originally unclassified but had gained its number by 1932.
Starting on the A914 at a simple T-junction south east of Kingskettle, the road heads north west into the village, where it follows the main street as it deviates around the church yard. Continuing northwards, the village is soon left behind and the road passes through fields before kinking to the left to pass under the railway, and so enter Ladybank. A TOTSO is quickly reached, with the B938 terminating from the west; indeed this route, which was classified in 1922, always finished here, even before the B9129 came into being.
We turn right and then left past the station and head through what may be an old market place, before the road narrows as it runs alongside the railway. The road then forks left as it works its way through the village, before kinking right onto a long straight out of town and up to the junction with the A92 a short distance further on.