“F6.5: the message written in rows and read off along a compass direction (each of the 16 points, and east then east-northeast or northeast in two stages), then or before a repeating key on the table”
F6.5 (added 2026-10-16, A14(a)). The known words are directions; read as instructions (C16(c)), they could name the route by which the grid is copied out. Routes: the 97 letters written in rows of w (2-96), read along lines parallel to one of the 16 compass points (the eight half-points as steps of one row and two columns), lines taken in either order; and two such stages in sequence for every ordered pair of E, ENE and NE at widths 2-48 ('east, then northeast'). Forward and inverse. Then a periodic key 1-26 on the standard or KRYPTOS tables in either order, decided exactly as 0134, against ten scrambled coppers.
The two clue words are directions: east, northeast. Perhaps they also say how the letters were moved: write the messagethe message The 97 letters of English that Jim Sanborn wrote and enciphered. in rows, then copy it out travelling east-northeast across the grid, or any other compass direction. We try every compass direction, every row width, and two-step versions (east, then northeast), each followed or preceded by a repeating secret wordthe secret word The word or string a cipher needs besides the method. on the sculpture's tables, and check them against the 24 known lettersthe known letters Sanborn has confirmed that positions 22 to 34 of the message read EASTNORTHEAST and positions 64 to 74 read BERLINCLOCK. and scrambled copies of the carved textthe carved letters The 97 letters cut into the copper at the CIA, shown at the top of every experiment page..
Words in the margin are defined on the glossary page.
1.1
The method at work
The carved letters go in at the top; the reading comes out at the bottom.
the idea
The known words are directions. Read as instructions, east and northeast could name the route by which the grid of letters is copied out: along the rows, then up the diagonals.
the check
Every width, each of the 16 compass points as the direction of reading, lines taken either way, and east then east-northeast or northeast in two stages: 110,820 routes, then or before a repeating key on the sculpture's tables.
the bound
Shortest key that fits K4: 21 after, 25 before, as on the copies; K4 above every copy in 1 of 52 cells, a copy 0-1.
2
Best candidate against the known letters
This experiment produced no candidate: the search ruled everything out before a full text was built. Its product is the bounded negative in section 7.
3
Walkthrough, by hand
Redo the method on a few letters with pencil and paper.
Write the 97 letters in rows of 10.
Travel east-northeast: one row up, two columns right. Every line of cells in that direction is read from its lower-left end.
Take the lines in order, starting from the top-left corner, and copy each out: that is the moved text.
Note where each of the 24 known letters lands and the carved letter there.
With a key of length p on the table, two known letters landing a multiple of p apart must force the same key letter.
Repeat for every direction, width and order, the key before or after, and on scrambled copies.
the worksheet: the first steps by hand, on squared paper
4
Worked example, generated
The same steps run by the code on the real letters.
rows of 10, read east-northeast (one row up, two columns right), lines from the top-left corner
first 20 message places read: 1 2 11 3 12 4 21 13 5 22 14 6 31 23 15 7 32 24 16 8
place letter lands at copper there
22 E 10 H
23 A 14 S
24 S 18 F
64 B 57 I
65 E 63 B
74 K 67 V
5
Hypothesis, for a cryptanalyst
Family, key space, the constraint under test, and the clues it reads.
C16(c) ('The final passage will lead in several directions. The word directions is, I use intentionally', 2010, knowledge/sources/nyt-2010-berlin-clue.txt), C1(a) (rows written, columns read: the matrix code, knowledge/sources/cnn-2005-sanborn-interview-transcript.txt), C3(a) (spatial systems). Route: cell (r, c) holds message place r w + c; direction (dr, dc) in {N (-1,0), NNE (-2,1), NE (-1,1), ENE (-1,2), E (0,1), ESE (1,2), SE (1,1), SSE (2,1), S, SSW, SW, WSW, W, WNW, NW, NNW (negatives)}; lines are the classes of dc r - dr c, read in increasing projection dr r + dc c, lines in increasing or decreasing class. Singles: 16 x 2 x widths 2-96. Doubles: (E, ENE, NE)^2 ordered x line orders x widths 2-48 each. Forward and inverse, duplicates removed. Key: periodic tableau 1-26 after (A) or before (B), 8 classes; a period is live if no slot holds two different forced letters. Statistic fixed before the run (0134's): cells where K4's live count is above every copper's, against each copper's count against the rest.
6
Prediction
Written before the run; the result decides it.
As in 0134: nothing live below key length 20 beyond the coppers' rate; K4 above every copper in no more cells than the most any copper manages against the rest. Zero candidates.
7
Method
Build every route: singles and doubles as stated, forward and inverse; remove duplicates.
For each route, class and text, the key letter each known letter forces at its slot (order A: landing place mod p; order B: message place mod p).
Count live periods 1-26 per order on K4 and ten coppers; list K4's settings live below 20.
Compare cell by cell with the fixed statistic.
8
Result and bounds
The harness's record: candidates, gates, loss, and the negative result this experiment leaves behind.
0candidates returned
0passed every gate
0/24known letters, best
–lowest loss
nonechampion before
110,820 distinct routes x 8 classes x 2 orders, periods 1-26. Shortest live on K4: A 21, B 25; coppers A 21, B 25. K4 settings live below 20: A 0, B 0. K4 above every copper in 1 of 52 cells; null 0-1. Stop queue: False.
What was searched, as the harness recorded it.
family
compass-direction reading routes (16 points, either line order, widths 2-96; E/ENE/NE pairs at widths 2-48), then or before a periodic tableau key