When do merchants restock in Might and Magic VI: The Mandate of Heaven?

What does not work:

• “Rest & Heal 8 Hours”
• Nipping into the competitor's shop
• Teleport away (for example, going to the Castle Ironfist arena and back)
• Load another area (such as Temple of Baa) and return

Works, but is clunky and expensive at the start of the game:

• “Raise the flag and hoist the sail!” twice

Is there a more convenient rule of thumb for when vendors restock?

Solution 1:

In most cities, the restock time is one week (on a fixed day). If you ask the NPCs in the city, you might find some that tell you the day. The line is something like this "We get new supplies each Monday." (roughly translated from the German version). However, I'm not sure if it is the same day for every city.