To find the cache you will have the pleasure to check out 4 locations, and get four numbers (a, b, c, d):
At these coords you will find 4 old borderstones:
a) N59 56.762 E10 45.584
What is the number on this stone? a=?
b) N59 56.445 E10 45.152
There is a letter on the opposite (south) building,
which number/rank does the letter have in the alphabet? b=?
c) N59 56.314 E10 44.985
Use the number on the stone: Subtract the first digit from the last c=?
d) N59 56.097 E10 44.633
What is the number on this stone? d=?
These stones are 4 of totally 81 border stones that marked the town border of Kristiania/Oslo from 1878 to 1948. All stones are marked with a crown, a number - and on one side the letter K (=Kristiania) and the other side A (=Aker). Kristiania was the name of Oslo until 1924. Almost 40 of the 81 stones can still be seen in Oslo.
The cache (5th location) is placed on the bank of the river Akerselva, of which a short section made part of the borderline 1878-1948. But the target itself is not at the former border.
To find its coords, insert and calculate the numbers above:
N59 56.((a x 2) + (b x 3)) E10 45.((d x 7) + b - (c x 4))
If you make this quest a round trip, from a) and back to a), it is less than 5 km.
The cache is double themed:
Waterways of Oslo and Old Oslo Borderstones.
Action close to the cache:
Theme A: Waterways of Oslo - creeks and rivers
~ ~ ~
These geocaches are placed along the waterways of Oslo (from west to east and downstream): /
Disse geocacher er plassert ved Oslos vannveier (rekkefølge fra vest til øst og nedstrøms):
~ Heggelielva: PPJ #15 Heggelielva, Gryta
~ Tverrelva: PPJ #27 Midtre Lysedammen
~ Sørkedalselva: gekoh #05: Surka and PPJ #14 Overfloden, river of Oslo
~ Lysakerelva: PPJ #18 Peter's Crossing, Lysakerelva Spilleboksen,
PPJ #43 Wet Arena, SQUAWK#1 The New Bridge at Fåbro
and SQUAWK#2 The Mill Falls of Lysaker
~ Mærradalsbekken: PPJ #26 Sneak Creek
~ Styggedalsbekken and Skådalsbekken: PPJ #22 Twin Creeks
~ Hoffselva: PPJ #19 Court Creek Coming
~ Sognsvannsbekken: PPJ #2 Sognsvannsbekken creek,
HYSSE#19 "Spring Cache" and Xmas #3, many xings
~ Frognerelva: The Park, Beer Corner, NWG # 7 Cold Turkey in Oslo
and PPJ #42 Frognerelva Exit
~ Akerselva: RN#1 Frysja, gekoh #02: Nydalsbakken , PPJ #64 - Twisted,
Drama Behind You, Triple Islands, Jerusalem and the bridge that is not, Olsen Special,
PPJ #23 Borderline North, As Close As You Get, PPJ #44 Aamodt Bru,
AG#24 - Canvas Fall and Akerselva exit
~ Hovinbekken: HYSSE#9 "GreenTrashCache"
~ Alna: Lillomarka Rundt #3 - Alna, AG#17 - The old bridge of Alna,
Alnaparken, AG#23 - Cotton Fall and HYSSE#5 "A RiverDance"
~ Haugerudbekken: AG#8 - Soda creek
~ Østensjøbekken: AG#6 - Silent creek
~ Ljanselva: Rotten Bastard
7 rivers in Oslo are falling into the Oslo Fjord:
Lysakerelva, Mærradalsbekken, Hoffselva, Frognerelva, Akerselva, Alna and Ljanselva.
Theme B: Old Oslo Borderstones
¤ ¤ ¤
These geocaches are placed along the the Kristiania/Oslo border 1878-1948 (from east to west, like the stones are numbered):
¤ South: Borderstone #2 at AG#7 - BorderStart, Borderstone #11: Very close to AG #5 Åreknuten and Borderstones #16 and #17 less than 100 meters from HYSSE#6 "OsloCloseUp".
¤ Southeast: Only 170 meters east of the existing Borderstone #35 (N59 54.260 E10 47.848) is HYSSE#5 "A RiverDance" and 110 meters south of the disappeared Borderstone #36 is HYSSE#10"TrainJunkie"
¤ East: The 3 first locations for PPJ #24 Borderline East
¤ Northeast: Borderstone #51, PPJ #51 Urban Valley
¤ North corner: A short section of Akerselva, close to Triple Islands, formed the northeast corner of the city (Borderstone #61, disappeared)
¤ Northwest corner: The first 4 locations for this Multicache
The cache is visible, but not easy to spot! Bring a camera or some bread for the ducks, to confuse the muggles.