As a Challenge cache you will need to list in your Found It log entry the NINE (9) caches from 'your State' that qualify you for the 'Specialist' Find here. (Obviously) They are all of the rating of Difficulty 4, and the Terrain ratings required are: T1, T1½, T2, T2½, T3, T3½, T4, T4½, and T5.
The minutes for this Challenge cache are to be added to S31º 's' E152º 'e':

Rules:
1/ (The particular consecutive TWENTY FOUR MONTHS is the time frame that you select. So it could be when you first started caching, OR, the most recent consecutive 24 months.) This DOES NOT have to be the same time period required for other in the Nine Tree Trail Series.
2/ This is may be extended by a further TWELVE MONTHS for each additional different Type of cache you are able to include in your list. SO, if you only use one particular Type of cache (no matter WHAT Type it is) it is still up to you to select the particular 24 consecutive months to get your list of caches from. BUT, if you choose (or are able) to include x 4 different Types of caches in your list each with a unique Terrain rating then you would have 5 years in the past of logging this cache to gain your State list from - for example. Wow is that even possible.
3/ In your Found It log (or Note, if getting ready to come and find it), please include your State of Origin, and the time frame you are using for this cache. Then, for each of the x 9 qualifying caches: Terrain rating, GC code, Cache Name, Type, Date Found.
re 3/ a) Alternate ways to show qualifying caches, 4/ 'Wildcard', and 5/ Cache Owner exceptions see the D1 x 9 T State Challenge, GC5D8TN.
"So, I don't have a 'State of Origin' (or subsequently adopted a State), can I still qualify?"; Okay, if you otherwise qualify you are still welcome to log a Find for this one, but won't automatically be able to Find the Final State of Origin Challenge cache; but you are on your way to qualifying for the Victorian challenge cache. (Country of Origin is acceptable for our overseas visitors).
Below is a statistical representation of the quantity of Difficulty 4 caches that were active in the Australian States in September, 2014. As can be seen the Northern Territory and Tasmania don't have a full complement of D4 caches, so any bordering state could be chosen for those missing Terrain combinations, ie, Queensland, South Australia, or Western Australia, or Victoria, and your State of Origin would still be accepted. PLEASE DON'T take these numbers 'as Gospel', as we all know that new caches will be added, and others Archived.

New South Wales: 1/12/12 to 30/4/14 (x 3 Types -> 4 years)
T1, GC415M0, Sutherland Shire Cycleways - Cache #19, Unknown, 31/5/13
1½ GC2AQ3G, Cryptozoology, Multi, 3/8/13
T2, GC1JHXJ, Trailblazers, Trad, 24/2/14
2½ GC1VZY0, BETWEEN A ROCK AND A HARD PLACE, Trad, 2/12/13
T3, GC1TZGB, Islandhoppper 1, Trad, 12/12/12
3½ GCHY6T, 1905, Trad, 30/5/13
T4, GCRVZ5, Sudoku - Hard, Unknown, 16/5/13
4½ GC3D28Q, Say What!, Unknown, 18/7/12
T5, GC4J8EZ, 4 x 4 Challenge, 29/12/13