In Ruokolahti the E10 trail system consists of two loops, 40 km together. The 40 km route combines the above 18 km Lääväkorpi-Syväjärvi trail with this Mustakulkkula trail loop.
The Mustakulkkula loop starts at the southern end of Syväjärvi, where the above Lääväkorpi trail turns back. On the shore of lake Kaituri you'll find a shelter and a campfire site.
Departure/finish is at the Ruokolahti sports field (Metsolantie 3). If you want to go counter-clockwise, start from the right side of the footbridge behind the sports field. You can also start the trip from Lumikontie or Puumalantie.