Z408 Kill Cascade

The complete cascade — every step, pen and paper, no computer.

THE STARTING POINT

The Hardens solved Z408 in one week in 1969. Their crib was KILL. It appears 4 times in the cipher — a confirmed, rock-solid crib.

KILL gives you 3 letters: K, I, L.

That's it. That's the starting point. One word. Three letters. Watch what happens.

STEP 1: KILL (the crib)

How: KILL appears 4× in Z408. Pattern confirmed. Crib locked. Letters: K, I, L Known: 3 unique

I LIK. KILLI.. ....L. ....... I. I. .. .... ... I. I. .... ... ....
KILLI.. .IL. .... I. ... ....... ....... ... I. ... .... .........
..I..L .. .LL .. KILL ......I.. .I... .. ... .... ...ILLI.. ......... I.
I. .... ...... .... ....I.. .... ...K. ... .I.. . .I.L ... .... .... ..
I. I. .... .... I .I. I .ILL .. ...... I. .....I.. ... .LL ... I ....
KILL.. .ILL ...... .. .L.... I .ILL ... .I.. ... .. .... ....... ...
.ILL ... .. .L.. .... .. .... .. ..LL...I.. .. .L.... ... .. .....LI..
.....I.........I.I

Revealed: 83/408 (20%)

STEP 2: KILLED/KILLER — visible as "KILL.."

How: KILL is known. "KILL.." has two unknown letters. Either KILLED or KILLER — both contain E. We don't need to decide yet. Either way we now have E. New letters: E Known: K, I, L, E (4 unique)

I LIKE KILLI.. .E..LE .E....E I. I. .. .... ... I. I. ...E ... ....
KILLI.. .IL. ...E I. ..E ....E.. .E....E ... I. ..E .... ....E....
..I..L .. .LL .. KILL ...E..I.. .I.E. .E ..E .... ...ILLI.. E..E.E..E I.
I. E.E. .E..E. .... .E..I.. .... ...K. ... .I.. . .I.L ..E .E.. .... ..
I. I. ...E ..E. I .IE I .ILL .E .E.... I. .....I.E ... .LL ..E I ...E
KILLE. .ILL .E...E .. .L..E. I .ILL ... .I.E ... .. ...E .E....E ...
.ILL ... .. .L.. .... .. .... .. ..LLE..I.. .. .L..E. ... .. ...E.LI.E
E.E..IE.E.E....I.I

Revealed: 136/408 (33%)

STEP 3: KILLING — visible as "KILLI.."

How: K, I, L, E known. "KILLI.." — obviously KILLING. New letters: G, N Known: K, I, L, E, G, N (6 unique)

I LIKE KILLING .E..LE .E....E I. I. .. .... ..N I. I. ...E ..N ...N
KILLING .IL. G..E IN ..E ....E.. .E....E ..N I. ..E .... ..NGE....
.NI..L .. .LL .. KILL ...E..ING .I.E. .E ..E .... ...ILLING E..E.EN.E I.
I. E.EN .E..E. ...N GE..ING .... ...K. ... .I.. . GI.L ..E .E.. .... ..
I. I. ...E ..EN I .IE I .ILL .E .E...N IN .....I.E .N. .LL ..E I ...E
KILLE. .ILL .E...E .. .L..E. I .ILL N.. GI.E ... .. N..E .E....E ...
.ILL ... .. .L.. ...N .. .... .. ..LLE..ING .. .L..E. ... .. ...E.LI.E
E.E..IE.E.E....I.I

Revealed: 171/408 (41%)

STEP 4: GIVES — visible as "GI.E."

How: G, I, E known. "GI.E." — obviously GIVES. New letters: V, S Known: K, I, L, E, G, N, V, S (8 unique)

I LIKE KILLING .E..LE .E...SE I. IS S. .... ..N I. IS ...E ..N ...N
KILLING .IL. G..E IN ..E ....ES. .E...SE ..N IS ..E ..S. ..NGE...S
.NI..L .. .LL .. KILL S..E..ING GIVES .E ..E ..S. ...ILLING E..E.EN.E I.
IS EVEN .E..E. ...N GE..ING .... ...KS ... .I.. . GI.L ..E .ES. .... ..
I. IS ...E ..EN I .IE I .ILL .E .E...N IN .....I.E .N. .LL ..E I ..VE
KILLE. .ILL .E...E .. SL.VES I .ILL N.. GIVE ... .. N..E .E...SE ...
.ILL ... .. SL.. ...N .. S... .. ..LLE..ING .. SL.VES ... .. ...E.LI.E
E.E..IE.E.E....I.I

Revealed: 200/408 (49%)

STEP 5: THRILLING — visible as "...ILLING"

How: I, L, N, G known. "...ILLING" — obviously THRILLING. New letters: T, H, R Known: K, I, L, E, G, N, V, S, T, H, R (11 unique)

I LIKE KILLING .E..LE .E...SE IT IS S. ...H ..N IT IS ..RE ..N TH.N
KILLING .IL. G..E IN THE ..RREST .E...SE ..N IS THE ..ST ..NGER..S
.NI..L .. .LL T. KILL S..ETHING GIVES .E THE ..ST THRILLING E..EREN.E IT
IS EVEN .ETTER TH.N GETTING ...R R..KS ... .ITH . GIRL THE .EST ..RT ..
IT IS TH.E .HEN I .IE I .ILL .E RE..RN IN ..R..I.E .N. .LL THE I H.VE
KILLE. .ILL .E...E .. SL.VES I .ILL N.T GIVE ... .. N..E .E...SE ...
.ILL TR. T. SL.. ...N .R ST.. .. ..LLE.TING .. SL.VES ..R .. ..TERLI.E
E.E.RIETE.ETHH.ITI

Revealed: 269/408 (65%)

STEP 6: FORREST — visible as "..RREST"

How: R, E, S, T known. "..RREST" — obviously FORREST (the Zodiac's misspelling). New letters: F, O Known: K, I, L, E, G, N, V, S, T, H, R, F, O (13 unique)

I LIKE KILLING .EO.LE .E...SE IT IS SO ...H F.N IT IS .ORE F.N TH.N
KILLING .IL. G..E IN THE FORREST .E...SE ..N IS THE .OST ..NGERO.S
.NI..L OF .LL TO KILL SO.ETHING GIVES .E THE .OST THRILLING E..EREN.E IT
IS EVEN .ETTER TH.N GETTING .O.R RO.KS OFF .ITH . GIRL THE .EST ..RT OF
IT IS TH.E .HEN I .IE I .ILL .E RE.ORN IN ..R..I.E .N. .LL THE I H.VE
KILLE. .ILL .E.O.E .. SL.VES I .ILL NOT GIVE .O. .. N..E .E...SE .O.
.ILL TR. TO SLO. .O.N OR STO. .. .OLLE.TING OF SL.VES FOR .. .FTERLIFE
E.EORIETE.ETHH.ITI

Revealed: 308/408 (75%)

STEP 7: PEOPLE — visible as ".EO.LE"

How: E, O, L known. ".EO.LE" — obviously PEOPLE. New letters: P Known: K, I, L, E, G, N, V, S, T, H, R, F, O, P (14 unique)

I LIKE KILLING PEOPLE .E...SE IT IS SO ...H F.N IT IS .ORE F.N TH.N
KILLING .IL. G..E IN THE FORREST .E...SE ..N IS THE .OST ..NGERO.S
.NI..L OF .LL TO KILL SO.ETHING GIVES .E THE .OST THRILLING E.PEREN.E IT
IS EVEN .ETTER TH.N GETTING .O.R RO.KS OFF .ITH . GIRL THE .EST P.RT OF
IT IS TH.E .HEN I .IE I .ILL .E RE.ORN IN P.R..I.E .N. .LL THE I H.VE
KILLE. .ILL .E.O.E .. SL.VES I .ILL NOT GIVE .O. .. N..E .E...SE .O.
.ILL TR. TO SLO. .O.N OR STOP .. .OLLE.TING OF SL.VES FOR .. .FTERLIFE
E.EORIETE.ETHHPITI

Revealed: 315/408 (77%)

STEP 8: BECAUSE — visible as ".E...SE"

How: E, S known. ".E...SE" — obviously BECAUSE. New letters: B, C, U, A Known: K, I, L, E, G, N, V, S, T, H, R, F, O, P, B, C, U, A (18 unique)

I LIKE KILLING PEOPLE BECAUSE IT IS SO .UCH FUN IT IS .ORE FUN THAN
KILLING .IL. GA.E IN THE FORREST BECAUSE .AN IS THE .OST .ANGEROUS
ANI.AL OF ALL TO KILL SO.ETHING GIVES .E THE .OST THRILLING E.PERENCE IT
IS EVEN BETTER THAN GETTING .OUR ROCKS OFF .ITH A GIRL THE BEST PART OF
IT IS THAE .HEN I .IE I .ILL BE REBORN IN PARA.ICE AN. ALL THE I HAVE
KILLE. .ILL BECO.E .. SLAVES I .ILL NOT GIVE .OU .. NA.E BECAUSE .OU
.ILL TR. TO SLO. .O.N OR STOP .. COLLECTING OF SLAVES FOR .. AFTERLIFE
EBEORIETE.ETHHPITI

Revealed: 367/408 (89%)

STEP 9: MUCH — visible as ".UCH"

How: U, C, H known. ".UCH" — obviously MUCH. New letters: M Known: K, I, L, E, G, N, V, S, T, H, R, F, O, P, B, C, U, A, M (19 unique)

I LIKE KILLING PEOPLE BECAUSE IT IS SO MUCH FUN IT IS MORE FUN THAN
KILLING .IL. GAME IN THE FORREST BECAUSE MAN IS THE MOST .ANGEROUS
ANIMAL OF ALL TO KILL SOMETHING GIVES ME THE MOST THRILLING E.PERENCE IT
IS EVEN BETTER THAN GETTING .OUR ROCKS OFF .ITH A GIRL THE BEST PART OF
IT IS THAE .HEN I .IE I .ILL BE REBORN IN PARA.ICE AN. ALL THE I HAVE
KILLE. .ILL BECOME M. SLAVES I .ILL NOT GIVE .OU M. NAME BECAUSE .OU
.ILL TR. TO SLO. .O.N OR STOP M. COLLECTING OF SLAVES FOR M. AFTERLIFE
EBEORIETEMETHHPITI

Revealed: 383/408 (93%)

STEP 10: WITH — visible as ".ITH"

How: I, T, H known. ".ITH" — obviously WITH. New letters: W Known: K, I, L, E, G, N, V, S, T, H, R, F, O, P, B, C, U, A, M, W (20 unique)

I LIKE KILLING PEOPLE BECAUSE IT IS SO MUCH FUN IT IS MORE FUN THAN
KILLING WIL. GAME IN THE FORREST BECAUSE MAN IS THE MOST .ANGEROUS
ANIMAL OF ALL TO KILL SOMETHING GIVES ME THE MOST THRILLING E.PERENCE IT
IS EVEN BETTER THAN GETTING .OUR ROCKS OFF WITH A GIRL THE BEST PART OF
IT IS THAE WHEN I .IE I WILL BE REBORN IN PARA.ICE AN. ALL THE I HAVE
KILLE. WILL BECOME M. SLAVES I WILL NOT GIVE .OU M. NAME BECAUSE .OU
WILL TR. TO SLOW .OWN OR STOP M. COLLECTING OF SLAVES FOR M. AFTERLIFE
EBEORIETEMETHHPITI

Revealed: 392/408 (96%)

STEP 11: WILD — visible as "WIL."

How: W, I, L known. "WIL." — obviously WILD. New letters: D Known: K, I, L, E, G, N, V, S, T, H, R, F, O, P, B, C, U, A, M, W, D (21 unique)

I LIKE KILLING PEOPLE BECAUSE IT IS SO MUCH FUN IT IS MORE FUN THAN
KILLING WILD GAME IN THE FORREST BECAUSE MAN IS THE MOST DANGEROUS
ANIMAL OF ALL TO KILL SOMETHING GIVES ME THE MOST THRILLING E.PERENCE IT
IS EVEN BETTER THAN GETTING .OUR ROCKS OFF WITH A GIRL THE BEST PART OF
IT IS THAE WHEN I DIE I WILL BE REBORN IN PARADICE AND ALL THE I HAVE
KILLED WILL BECOME M. SLAVES I WILL NOT GIVE .OU M. NAME BECAUSE .OU
WILL TR. TO SLOW DOWN OR STOP M. COLLECTING OF SLAVES FOR M. AFTERLIFE
EBEORIETEMETHHPITI

Revealed: 399/408 (97%)

STEP 12: YOUR — visible as ".OUR"

How: O, U, R known. ".OUR" — obviously YOUR. Also confirms YOU (.OU) and MY (M.) and TRY (TR.). New letters: Y Known: K, I, L, E, G, N, V, S, T, H, R, F, O, P, B, C, U, A, M, W, D, Y (22 unique)

I LIKE KILLING PEOPLE BECAUSE IT IS SO MUCH FUN IT IS MORE FUN THAN
KILLING WILD GAME IN THE FORREST BECAUSE MAN IS THE MOST DANGEROUS
ANIMAL OF ALL TO KILL SOMETHING GIVES ME THE MOST THRILLING E.PERENCE IT
IS EVEN BETTER THAN GETTING YOUR ROCKS OFF WITH A GIRL THE BEST PART OF
IT IS THAE WHEN I DIE I WILL BE REBORN IN PARADICE AND ALL THE I HAVE
KILLED WILL BECOME MY SLAVES I WILL NOT GIVE YOU MY NAME BECAUSE YOU
WILL TRY TO SLOW DOWN OR STOP MY COLLECTING OF SLAVES FOR MY AFTERLIFE
EBEORIETEMETHHPITI

Revealed: 407/408 (99%)

STEP 13: EXPERENCE — visible as "E.PERENCE"

How: Every other letter known. "E.PERENCE" — obviously EXPERENCE. The Zodiac's misspelling of EXPERIENCE. Of course. New letters: X Known: K, I, L, E, G, N, V, S, T, H, R, F, O, P, B, C, U, A, M, W, D, Y, X (23 unique)

I LIKE KILLING PEOPLE BECAUSE IT IS SO MUCH FUN IT IS MORE FUN THAN
KILLING WILD GAME IN THE FORREST BECAUSE MAN IS THE MOST DANGEROUS
ANIMAL OF ALL TO KILL SOMETHING GIVES ME THE MOST THRILLING EXPERENCE IT
IS EVEN BETTER THAN GETTING YOUR ROCKS OFF WITH A GIRL THE BEST PART OF
IT IS THAE WHEN I DIE I WILL BE REBORN IN PARADICE AND ALL THE I HAVE
KILLED WILL BECOME MY SLAVES I WILL NOT GIVE YOU MY NAME BECAUSE YOU
WILL TRY TO SLOW DOWN OR STOP MY COLLECTING OF SLAVES FOR MY AFTERLIFE
EBEORIETEMETHHPITI

Revealed: 408/408 (100%)

Done.

FINAL SUMMARY

THE POINT

One word. KILL. Three letters. Thirteen obvious fills later: 100% decoded.

No computer. No software. No 650,000 attempts. No postcard. No SLAVES. No PARADICE.

Just KILL → cascade → done.

This is exactly what the Hardens did in 1969. One word. One week. Pen and paper.

The Zodiac's ciphers were never hard. They never were.

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