Solution to Problem 23: "Letter Bourse #1"

Five letters will be in every row and column, so two cells in every row and column will be blank.  When we identify the two blank cells in a row or column, we will say that the others will be "filled in", and illustrate this by painting the cell yellow.

E1 cannot be D (because D is the leftmost entry in row 1), so E1 must be blank.  E3 also cannot be D, so E2 must be D.   Also, of B2 and C2, one is B and the other is blank.  Therefore, A1, D1, F1, and G1 are all filled in.  A1 is D and G1 must be C, so A3 and G2 are blank and F2 is C.  

Of G5 and G6, one is E and the other is blank, so G3, G4, and G7 are all filled in.G4 is B.

Of A2 and A5, one is A and the other is blank, so A4, A6, and A7 are all filled in.   A7 is C, so B7 is blank.
G3 is not B or C (since they are already in the G column) or D (which is the leftmost entry in row 3) or E (which is either at G5 or G6), so it is A.  G7 isn't A, B, C, or E, so it must be D, so F7 is blank and C7, D7, and E7 are filled in.   C7 is E and E7 is B, so D7 must be A. 

D1 isn't B, C, or D (already in row 1) or A (column D), so it is E, and F1 must be A.

A6 isn't A, C, or D (already in column A) or E (the rightmost entry in row 6), so it is B, and A4 must be E.
F4 isn't A or C (column F) or B or E (row 4) or D (the bottom entry in column F), so it must be blank, so F3, F5, and F6 are filled in.  F6 is D, so G6 must be E.  G5 is blank, so F5 is E.   F3 must be B.
One of the cells in column B must be an E; it cannot be B3 so it must be B2.  A2 must be A, B2 must be B. C1 and A5 are both blank.  B5, C5, D5, and E5 are filled in.  B5 is A, so B6 is C.

The E in column E must be at E3, so E2 is D.   E5 can only be C.  C5 is not A, C, E (row 5) or B (topmost in column C), so it is D abd D5 is B.  D2 and D6 cannot be A, B, C, D, or E, so they must both be blank; C2 is B. 

D3 isn't A, B, E (column D) or D (leftmost in row 3), so it is C, and D4 is D.  B4 must be blank, so B3 is D.  C3 is blank, so C6 is A and E6 is blank.  E4 is A and C4 is C.
The rows in order are DBEAC AEBDC DCEBA ECDAB ADBCE BCADE CEABD.

Comments: I had only seen the Letter Bourses once before.  Perhaps it was in a Games World of Puzzles coverage of a previous WPC contest.  I recalled enjoying them, but I had forgotten the schemata for solving them, so I didn't try them during the contest.  Even though these two puzzles were also fun to solve, it took me long enough that I'm glad I didn't spend any of my precious 90 minutes on them.