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Explorer 120 Challenge Mystery Cache

Hidden : 02/19/2012
4 out of 5
1.5 out of 5

Size: Size:   regular (regular)

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Geocache Description:

This is the second of our Explorer Challenge series based on British Ordnance Survey grid squares as depicted on Explorer maps.

The cache is not at the published location which is the centre point of the playing area for this challenge.

To complete the challenge you need to find a total of 120 different caches.

What is the Explorer 120 Challenge?

The cache is called the Explorer 120 Challenge because each of the 120 different caches you need to have found to qualify must be in a different British Ordnance Survey grid square as depicted on the Explorer 120 Chichester South Harting & Selsey map.
The caches can be of any type, previous finds qualify (including those finds now archived and events attended (even if you were the host)), in fact just about any cache other than those you have placed yourself can be counted.
To find out more about this and other Explorer Challenge caches, go to which has been created to complement the cache series.

The grids on the map "start" in the north west corner near East Meon at SU 68 000 22 000
and "finish" to the east of Selsey Bill at SZ 90000 92000 (not shown as its in the sea!), so giving a possible thirty (92 to 22) northing squares and twenty two (68 to 90) easting squares. 660 squares in total in which you need to find a cache in 120 different squares to qualify.

From personal experience I know how time consuming trying to determine which of 660 squares of an OS map a cache qualifies for, although of course the British Grid reference is given at the top of each cache page just below the main co-ordinates shown in bold, as circled below.

For the purposes of this challenge the published co-ordinates of all caches, including Unknown/Mystery and Multi caches are those that are to be used when determining which square a cache counts towards.

To help those of you that want to plan your finds a GSAK Macro has been written which produces a web page of your finds and any unfound caches in your current GSAK database selection that count toward this cache.

UPDATE JULY 2017:there is now a checker for this challenge, see

When you have found the 120 caches you need to provide proof of that fact to be eligible to claim a find on the cache; this can be via one of any number of different methods you may have available:

  1. Manually List the 120 cache codes and names in corresponding grid reference order in your found log!
  2. Paste the output of the checker into your log
  3. Create a public bookmark list<>/li>
  4. Send the GSAK Macro generated file to us via our profile or add it to your profile page
  5. Send us your "My Finds" Pocket Query and we will run the GSAK Macro for you and let you know if you qualify and if not which squares you still need to find a cache in to qualify

Any finds without proof of qualification will of course be deleted! Have fun!

League table of squares filled by finders shown below: (those in grey have not found the cache as yet)

Position Cacher Squares Filled Date
1 Mellers 349 16/10/2012
2 Broyleboxers 294 22/02/2012
3 Mario McTavish 290 22/02/2012
4 Aldwick Subs 281 15/03/2012
5 Qrang 280 29/04/2012
6 NuJerico 279 29/02/2012
7 Ann_and_Brian 279 01/03/2012
8 ExplorerOlway 262 02/03/2012
9 burtsbodgers 259 17/02/2013
10 Wandering Winghams 213 10/03/2012
11 MartyBartfast 203 03/02/2013
12 natterjacktoad 202 03/04/2012
13 KnotEar 193 21/09/2012
14 AllTheBridges 187 23/02/2012
15 Tebby In Chi 174 08/01/2013
16 PealRinger 171 19/07/2012
17 Tebbstickes 169 08/01/2013
18 Kitey 166 06/04/2012
19 d120874n 162 10/07/2012
20 KnightFamily1980 157 25/02/2012
21 MrCryptic 130 05/03/2012
22 Clipper247 128 19/02/2013
23 Karhut 128 10/03/2012
24 duncandillies 123 27/03/2012

Additional Hints (No hints available.)