The safe check formula was used to get approximate values for the pieces way back in 1876 when it was not widely known how to rate the pieces for exchange purposes. I am glad Juan's numbers so closely mirror my numbers that I published in Gothic Chess Review in the year 2000. Now I have an independent verification of my work.

One of the drawbacks you will notice is that a Queen is worth a Rook + Bishop EXACTLY, as are the other new pieces that combine two into one.

Also, saying a Rook was worth exactly two knights did not seem to make sense. So here is what I did to my numbers.

Chess players consider a Rook to be worth LESS than two minors, so that exchanging two minors for a Rook is discouraged. Minor pieces play a more active role in the opening and middlegame, and you can get into trouble playing something like Bxf7+ Rxf7 Nxf7 Kxf7 on an 8x8 chessboard against black's castled king. Black can get a more active attack going, winning more material with minors than you can defend with your unmoved rook pair.

So, chessmasters have scaled a Rook down to 5 points on the 8x8 board. But, as you see, we do not have to do this, since a Rook turns out to be less than two minors in Gothic.

But, we still have to "borrow" something from the 8x8 chessmasters. In knocking the Rook down to 5 pawns, the Queen was worth 8, not 9, as is the standard value in use today. What they did was add a one pawn bonus to the Queen since it could perform the R + B moves on only one square instead of two.

They basically multiplied the queen by 9/8ths on an 8x8 board. I just used the same scalar value and multiplied the Archbishop by 9/8ths. Doing this for our Q and C with the unscaled Rook would over-exaggerate their worth.

So, leaving the Rook alone in Gothic, and adding merit for the Archbishop only, you get:

Archbishop = 5.54 x 9/8 = 6.2325

Reinserting this into the list, we have:

Knight = 2.51
Bishop = 3.03
Rook = 5.67
Archbishop = 6.23
Chancellor = 8.18
Queen = 8.70

This has the nice result of the Archbishop being worth more than a Bishop pair, which is something I think we can agree is true. And, I would not trade my Archbishop for a Rook, and this correction fixes this as well.

So, the 8x8 chessmasters had to "tweak" values for their Rook and Queen, and we only had to "tweak" the Archbishop, so I think our model is fairly sound.