This is a house rule for Pulp Cthulhu which I keep forgetting, so I’m writing it down as an aide memoire for myself, more than anyone else!
Original credit to Seth Skorkowsky in his video on Call of Cthulhu Skill Mechanics (starting at the 28:12 mark).
My own house rule is slightly more generous than Seth’s, so I’m only using it in my Pulp Cthulhu games, rather than Classic Call of Cthulhu, where it suits the more optimistic tone.
When an investigator successfully uses a skill in play, the player should check the box beside that skill on the investigator sheet. With a Normal Success, check a line. With an Exceptional Success (or better), check a cross.
When rolling for skill improvement during the Hero Development Phase, apply a “bonus” die if a cross check was received for that skill. In this instance, use the highest “tens” dice, not the lowest, to determine success.
This house rule is well-tested and it’s been well-received by my players. Most importantly, it hasn’t caused skill ratings to explode!
Craig Pay 