Ornamentation and motifs in detail:
 

Runic inscription:

The fragmentary runic inscription goes over the two dragons. It starts at the neck of dragon 1 on the left between the beautiful paw and the cross. 

Dragon 1
Torsten (and) …  -stone raised …  (sfter) Estrid .? …  and after

× þorst… … …stain × rais… … -str-- …-… …uk × eftiR ×

Dragon 2 (continued)
Tunba…  Östen .?…”.

…tunba… × … × a… …R… …ain × …

Below are the facts mixed with my descriptive description of how I think the story of the runestone came to be. Here you have to try to separate fact and fiction on your own.  

About the runecarver

The rune carver's name is Osten!

Although the runic inscription is fragmentary, we can still determine that the runcarver is Östen by his unique details in images and ornamentation such as the floral cross and the small round animal with ribs.

When I try to follow Östen as a runecarver, I find him in the area around Bornsjön in Salem (14 km southeast of Birka) where some of his earlier runestones are found.

I find two of Östen's carvings that seem to be even older, his first tentative attempts in Huddinge church, Sö 299 and Botkyrka church Sö 283.

Huddinge church, Sö 299, page 276

Botkyrka church Sö 283, page 249

Later in his career and when he has become a little more confident in his work, he carves directly on granite slabs. That work is much heavier and more difficult than carving on a stone that is lying down and which you raise afterwards.

(It may seem unlikely that the same runecarver made these runestones but there is a common denominator and "common thread" to follow).
 

By the old road in Södertälje, up by today's Torekällberg, he carves Sö 312 with the rune animal to the right of Sö 313. (Östen has not carved the left one, Sö 311).

After this he carves the slabs in Vitsand, Sö 344b (or: Sö ATA322-1467-2011) and Kiholm, Sö 344a.

Vitsand, Sö 344b (or: Sö ATA322-1467-2011)

Kiholm, Sö 344a

When the water level in the 11th century was 5 meters higher than today, the two carvings were just above the water line.

Östen in Björkö village

Björkö village is next to the town of Birka. (Birka as a city disappears around the year 980 and Östen carves this U 6 in Björkö village around the year 1065).

The day Östen came to Björkö village to take part in his next project, he must have been very happy for the assignment. There on the ground lay a large stone of red sandstone that the client wanted Östen to carve a beautiful runestone from. Östen was also allowed to design the artwork freely according to his own inspiration.

Sandstone
It is much easier to carve in sandstone than in granite. Sandstone also does not break as easily when carving small details or making tight cuts.
Instead, the disadvantage of sandstone is that it does not withstand abrasion and that it easily breaks into pieces when struck and bumped. 

Östens ornamentation
Östen has always had a taste for pictures and animal motifs and he has long tried to imitate some of the motifs he saw in his younger days. The round animal with ribs reappears on several of his carvings, but it is only here on U 6 that it finally gets really good, the same goes for the beautiful paw.

Here on the lightly carved runestone in Björkö village, he unleashes all his creativity and fills the surface with beautiful ornamentation and images and of course the client's runic inscription.
 

The runestone is raised
The finished runestone was probably erected on a hill in the village's harbor with the image surface facing the water. It stood there for a long time in all its splendor and both welcomed and impressed the village's guests and visitors.

The runestone falls
After a long time, perhaps 100 to 200 years, the ground gives way to the weight of the runestone, perhaps after a long period of rain in autumn. The runestone falls forward with the carved surface towards the ground.

Perhaps the care of the rune stone had been neglected so that moss and lichen began to take over the surface of the stone, perhaps the color faded and flaked. Maybe the memory of the people in the runic inscription has started to fade?

Raising the heavy runestone again was going to be hard work that was left until later... then it was forgotten, more and more, until no one remembered that there was a runestone lying there on the ground with its back facing up.

The runestone is accidentally destroyed.
A few hundred years later, perhaps in the 15th-17th centuries, the memory of the runestone had been completely forgotten. One day when they were looking for suitable stones for the foundations of new houses in the village, the choice fell on the large red stone that had long lain above the old harbour.

The stone was too large to be used as it was and needed to be broken into pieces. Wood was piled up on the stone and fires were lit. After burning for a while and when the stone was very hot, cold water was thrown on the stone, which was immediately shocked and burst into pieces.

When the cracked pieces were turned over and it was seen that it was a runestone that had been destroyed, the pieces still had to become building material as it was intended from the beginning.

Pieces are found again
During the 19th century, several pieces of the old runestone began to appear in Björkö village during the rebuilding and renovation of old houses.

When "Uppland's runic inscriptions" were written in the 1940s, it was believed that the pieces belonged to different runestones, so they were named U 6, U 7 and U 8.

The latest find from the year 2012 makes it clear that all the pieces may belong to the same rune stone and a ten-piece puzzle begins to be put together.

Three runestones become one
The attempt to put the pieces together was successful and the result was that the ten fragments became a rune stone that was now named U 6.
 

The ten pieces of U 6 can be seen in the museum at Birka.

The fragments of U 6 known today (about 70%) are laid out like a big puzzle and can be seen in the museum at Birka. A full-scale image with colors can be found here in Runstensparken and the best image is perhaps the one you see here at the top of the web page!

30% of the carving is still missing...
Several parts of the runestone remain in or around the houses in Björkö village and are waiting to be found. But the smaller, but oh so important little pieces and shards after the runestone was split are left in the place where the runestone was first raised and later fell.

But we don't know the exact location, we think it's on a hill by the village harbor. The location should be clearly visible towards the bay for arriving boats and should be at least five meters above the lake's water surface today.

The rune stone should also have been near the road or path that existed between the harbor and the village so that whoever wished could easily walk up to the rune stone and study it more closely.

Reflection
I wonder how the boat crews experienced the carvings along the shipping trail, were they just decorative, beautiful and inviting or did they also give some kind of respect to the areas they were heading towards?

I also wonder if Björkö village was the last runic carving or if there are more further north in the fairway up towards the new Sigtuna or old Uppsala?
The carving at Vitsand was found by pure luck as recently as 2007, so there may be more...

If you want and can search for these "possible" runecarvings, you should search in the fairway north from Birka towards Sigtuna and Old Uppsala on clearly visible rock slab at least 4.5 meters above Lake Mälaren.

Visit the runestone.
It can be seen inside the museum at Birka

Links

1943
Upplands runinskrifter >
U6, U7 and U8 at page 9-10 (Swedish)

1992
Fornvännen > Page 230 (Swedish)
Two puzzle pieces are found (av U 6)

2012
Fornvännen > (Swedish)
About the latest find and the puzzle

2013-02-15
Birkaprojektet > A rune stone emerges. (Swedish)

2013-02-18
K-blogg > The puzzle continues (Swedish)

Runor > - Riksantikvarieämbetet
Map and runic inscription.

Google map > Find the runestone

kalle@runristare.se
If you want to be of help or have a question.
 

ALL RUNESTONES

Ekerö municipality

ADELSÖ >
has 5 known runestones

BIRKA >
has fragments from 9 known runestones

MUNSÖ >
has 3 or 4 known runestones

EKERÖ >
has 11 known runestones

FÄRINGSÖ >
has 27 known runestones

LOVÖ >
has 8 known runestones