The first of the two numbers codes dates from 1969. It is an extraordinary thing, the product of a playful and brilliant mind. It illustrates the complexity of both On Kawara's thought process and his art practice. You could argue that the Date Paintings and 'I GOT UP' postcards are simple ideas, when viewed from certain perspectives. There is nothing simple about what I'm about to convey. Which is partly why, as far as I'm aware, Code: Eight quintillion… is a code that was not decoded until Anders Delbom, Tommy Wrede and I did the business in March, 2024.

How do I put this strange episode across? Hiroko, in her July 1969 letter to Kasper Konig, enclosed what she referred to as an 'easy to crack' code of On's that was in English. It's possible that she meant another code, because the one I'm about to tell you about is not at all easy to crack, even if you're given a piece of essential information, which Hiroko did not seem to give Kasper Konig.

Here is the full title of the piece:


The above consists of just two numbers. An enormous whole number and a fraction of the number one. The whole number being the second one: 205,006,712,995,180. And the fraction being the first: 0.8802057201850504108.

Why are the numbers written out in words rather than expressed as numerals? For a start, it means that you have to get to the end of the list of words before you know whether you've got a huge number or a fraction, which is a bit disconcerting. Let's pause in the middle of that extraordinary title for a fraction of a second. Or for a very long time.

The full artwork? The catalogue,
On Kawara: Silence, shows five pages (six including the title page) of typed-out numbers as follows:


The work couldn't be dryer: just typed, spelled-out numbers in the same style as the title. The very first stage of decoding this text is to turn the spelled-out numbers into actual numbers, and to recognise that a question mark indicates the end of a line of numbers. So that first paragraph you can see at the top of the middle 'panel' on the left page goes from this (ignore the pencil marks):


To this:

500 0.210505106?
0.7450809 0.314175976?
60,425,071,901 675,039,976?
3 50,813. 0.40536?
5,901,802. 0.32704086?
8,101,047 601,901 0.30780031676?
50,930,805,513. 7,050,804,086?
2,000,805,513. 7,050,804,086?
0.9850103 0.3521679?
0.35809. 85.033?
59 243 0.3513?
5 0.75090804 206 95,076?

No-one would have been able to decode this back into a meaningful text, which may be why On Kawara mentioned the key to its decoding in a rare interview with Ursula Meyer in 1970. In her book,
Conceptual Art, published in 1972, Meyer wrote:

'About his code:
Eight Quintillion Eight Hundred and Two Quadrillion… (1969), which comprises five pages of spelled out astronomical numbers, Kawara said: "This code is easily cracked. You will find many answers which yield one question. I got this question from MAD Magazine (Number 128, July 1969)".'

As I say, a very rare example of On Kawara making a public statement about his work. Here is the cover of that
MAD Magazine:


MAD, for the benefit of a UK citizen, is like a cross between Viz and Private Eye. Clearly it was essential reading for Kawara's generation of bright young Americans. The map on the inside cover (see below, left) must have intrigued him, as would have the back cover (below, right). On Kawara was a heavy smoker who read, with heavy heart and suspect lungs, about the Vietnam War in the New York Times most days when he was living in NY in the 1960s.


Maybe in coming up with the code, On Kawara was simply putting off time before the Apollo 11 mission got underway on July 16. He was going to put a lot of Date Painting effort into that.

Maybe an evening at home in his Central Street studio started with On reading
MAD, enjoying the smart, sharp, funny, left-wing writing. Maybe when Hiroko went to bed, that was when On decided to make Code: Eight quintillion.. out of the double-page that must have been his favourite in the 48-page issue:


The full story of how this code was cracked is outlined in GAME ON (36). Suffice to say here, that artist Anders Delbom was integral to the solution, and that his puzzle-guzzling friend, Tommy Wrede, made the crucial leap. I am so proud of the team that spontaneously came together to help me out when help was exactly what was needed.

I think Anders must have said to Tommy that all we knew for sure was that the list of numbers called
Code: Eight quintillion… was explained by something in this issue of Mad Magazine (because On Kawara said that to Ursula Meyer and she wrote it down as I've already mentioned). I think Tommy must have looked at the numbers of the code as transcribed by me from streams of letters into numbers, the first being 'five hundred' represented as '500'. And I think he must have noticed the 500 at the beginning of panel one in the above double-page spread.


And his mind would have lit up - as mine subsequently did - at the sight of twelve panels with twelve lines in each panel, corresponding to the 12 paragraphs of spelled out numbers in the double-page spread in the On Kawara: Silence catalogue!

So let's go back to July 1969 and imagine On Kawara relating to this
MAD Magazine article for the first time. The reader is supposed to take one possibility from panel one, add the words 'paraded through' from the 'PROTEST NEWSPAPER STORY' control panel. Then take a sample phrase from panel two and add the word 'in' from the control panel. And so on. Here is panel 9 as a second example:


And here is the all-important control panel:


So, just choosing the first option each time, one would have:

'500 Yippies paraded through the streets in Berkeley today protesting the war in Vietnam. The demonstration began after a bearded male was seized by an off-duty policeman. When police arrived they were greeted by a shower of rocks and shouts of "Make love, not war!" The police responded with nightsticks. Speaking over television, this evening, the Governor declared a state of emergency and called for calm.'

The Vietnam mention makes me associate the above paragraph with On Kawara. What other choices might he have made? Would he have come up with a similar or a very different newspaper protest story?

Perhaps On Kawara went though a few further possibilities as he internally congratulated himself on the result of his cancer tests. Later (if not earlier, as it was on July 14 that Hiroko enclosed the typed pages of Code: Eight quintillion… in her letter to Kasper Konig), On realised he could use the MAD feature in another way. He could make a code out of it. (After all, not one of its 12 x 12 = 144 options had anything to do with cancer, or any other illness, or doctors, or hospitals.) So that the double-page spread could be recreated by anyone who had the code.

The feature starts '500 Yippies'. Which has to code into 500 0.210505106? This becomes the first line of Code, being 'Five hundred two hundred ten million five hundred five thousand one hundred and six millionths'. How did On put it to Ursula Meyers again?
'This code is easily cracked. You will find many answers which yield one question.' To which Ursula Meyers commented 'He enjoys punning the self-seriousness of artists - '"Recreation is more important than creation."

So that first line again, '500 YIPPIES'. 500 doesn't need coding, but 'YIPPIES' does::

Y = 02
I = 1
P = 05
P = 05
I = 1
E = 0
S = 6

If a number such as 02 (or 03 or 04 etc.) comes first, then it has to be expressed as 0.2. It's that which decides whether a number is going to be a multiple of one or a fraction. In other words the main thing about the appearance of the code, the very large or very small numbers, is an arbitrary thing!

Tommy Wrede went through panel one and found out the numbers corresponding to most of the letters of the alphabet. Though he may have had to go through a few panels before the more obscure letters like Q, X and Z were lined up with numbers, either 1 to 9, 01 to 09, or 10 to 60. The code in full:

A = 5
B = 07
C = 08
D = 3
E = 0
F = 06
G = 01
H = 04
I = 1
J = 10
K = 09
L = 4
M = 03
N = 9
O = 2
P = 05
Q = 20
R = 8
S = 6
T = 7
U = 50
V = 00
W = 60
X = 30
Y = 02
Z = 40

Numbers 70, 80 and 90 were not required as there are only 26 letters in the alphabet needing coding.

If you apply the above code to the two-number title, you get

0.8 8 02 05 7 2 01 8 5 05 04 1 08

20 50 0 6 7 1 2 9 9 5 1 8 0

Cryptography is the process of hiding or coding information so that only the person a message was intended for can read it. Which means that
Code: Eight quintillion… was written by On Kawara specially for Anders Delbom, Tommy Wrede, myself and everyone who is reading this chapter!

Perhaps I am over-egging this. Perhaps the solving of On Kawara's Code is not such a big deal. After all, the piece
Code: Eight quintillion was not really in the public realm until 2015, when On Kawara: Silence was published. At least I don't know of its earlier appearance in a publication. Though it seems to have been created in 1969 for a project by artist James Lee Byars (who was working in Belgium, hence Hiroko sending it to Kasper who was also living there at the time). And it was reproduced in the 2015 catalogue in such a way that the 'numbers' could hardly be read without a magnifying glass. My team may have made the very first protracted effort to solve the puzzle, so let's not be too hard on the rest of humanity which has largely been oblivious to the problem's existence. Besides, the work is almost an aside, completed (I'm supposing) in that period where On Kawara had been awaiting his cancer test results and not in the mood to be Date Painting. There were no Dates painted between July 4 and July 16, 1969.

Let's get things in perspective. On Kawara made
Code: Eight quintillion… in 1969, the same year - as we'll see, post-cancer scare - that he did a lot of other glorious work. He realised he needed to put into the public realm the information that the key to the code was a text in Mad Magazine, so he did that in the 1970 interview with Ursula Meyer. He published the piece called Code: Eight quintillion on his deathbed knowing that in maybe 100 years, maybe 1000, an art historian would decode it after coming across the key in Ursula Meyer's Conceptual Art. But along came Anders (who noticed the reference to Ursula Meyer's book in Heinz Nigg's diary from 1974), Tommy and myself, and the code was deciphered in 2024, just ten years after On Kawara's death.

The day in which the definitive cracking of the code was communicated to me from Sweden, I went for a walk and found myself passing from a Perthshire field where sheep were grazing to a crowded Manhattan street circa 1969. I bumped into On Kawara who handed me the piece of work called
Code in typed manuscript form.

On: "If you buy the current issue of of MAD Magazine the code is very easy to crack."

Me: "You mean it will take me about ten minutes flat?"

On: "Certainly not any longer than that."

Me: "Not fifty years and ten minutes then?"

On: "Ah, you've got me, Duncan. You must have been the cleverest boy in your class at school."

Me: " I don't know about cleverest. There was a team of us. I was the boy who couldn't stop playing games."


It makes a lot of sense that when On Kawara was putting
Whole and Parts together in 1995 for 1996 publication, he made reference to the importance of 1969 to his art and life by wrapping the 700-page tome in a text that commemorated both the MAD Mag code and, more importantly, the Moon landing.

Reproduced thanks to the understanding of the One Million Years Foundation.

A day or so after cracking Eight quintillion…, Tommy Wrede began to investigate whether the same code had been used in the creation of this sixteen-page code that began on the cover, ended on the back cover, and covered fourteen internal pages of the 700-pager.

0.42506729; 78,592,050,141,702;

Applying the code that was derived from
MAD Magazine dated July 1969, we can indeed decode the first two words as follows:

0.4 = H
2 = O
50 = U
6 = S
7 = T
2 = O
9 = N

That's us to the end of the first line of the
Whole and Parts cover.

7 = T
8 = R
5 = A
9 = N
20 = Q
50 = U
1 = I
4 = L
1 = I
7 = T
02 = Y

That's us half way along the third line of the
Whole and Parts cover. So there is no question about what is going on here: the July 1969 code from MAD Magazine is being used to code the Moon landing dialogue from that same July 1969. This time the result covers sixteen pages in densely written out numbers. Whereas next time (in 2011, as explained in the last essay) the paired coloured strokes would cover just nine pages and be included in the 2012 catalogue Date Painting in New York and 136 Other Cities.

However, Tommy Wrede has detected a difficulty. ("Houston, we have a problem.") This seems to be that certain zeroes have been missed out, and have to be added back in order for the Moon landing transcript to be adhered to.

So why the errors in the transcription? It may be that On Kawara was listening to a tape of the exchange between NASA and the astronauts, and it was his way of reproducing the fact that some words had been clipped either at the beginning or the end. Anyway, nothing could be clearer than that this - untitled - piece celebrates the moon landing.

What appears to be a completely low-key book cover - a list of very large numbers and fractions - is actually a capturing of collective human joy. For wasn't everyone watching the television or listening to the radio or reading the newspapers the day that mankind landed on the Moon? The day that astronauts walked and talked somewhere other than on planet Earth? But, as I say, what could have been an emotional work, almost a sentimental one, is made deadpan through the sensibility of On Kawara.