Stratford won in 2014 and 2022, second-placed Stacey Te Huia, of Alexandra, is yet to win the championship, third-placed Angus Moore, of Seddon, won in 2012 and 2020, and fourth-placed Leon Samuels, of Invercargill, won in 2021.
Te Kuiti shearer Jack Fagan, son of nine-time winner Sir David Fagan, and 2019 winner Paerata Abraham, of Masterton, are the only North Island shearers in the top 12 after the first round.
The PGG Wrightson Vetmed National Shearing Circuit is made up of five rounds, with shearers competing for points.
It starts in Alexandra in October with the fine wool section; moving to full wool hoggets in Waimate.
The third round will be at the New Zealand Corriedale Championships in Christchurch on November 11, the lamb shearing round will be at the Rangitikei Shearing Sports in Marton on February 4 and the last round, on second-shear sheep, will be at the Pahiatua Shears on February 26.
Based on points earned through those five rounds, the circuit final is fought out in Masterton by the top 12 shearers on the eve of the Golden Shears in Masterton on March 2-4.
The Circuit incorporates the McSkimming Memorial Triple Crown, which was first contested in 1972-1973, to establish the New Zealand champion all-breeds shearer each summer.
The Golden Shears has been the home of the finals since the first in March 1973, apart from two cancellations due to the Covid-19 pandemic.
The 2021 final was held in Te Kuiti, and last season's at Armidale Merino Stud, near Gimmerburn, Central Otago - the series' first final in the South Island.
The Circuit's 51st season is also the 21st year for PGG Wrightson, the major sponsor since 2002-2003. It is one of the longer-enduring sponsorships in New Zealand sport.
Points after the first round of the PGG Wrightson Vetmed National Shearing Circuit at the New Zealand Merino Shears in Alexandra on October 1
Nathan Stratford (Invercargill), 12pts, 1; Stacey Te Huia (Alexandra), 11pts, 2; Angus Moore (Seddon), 10pts, 3; Leon Samuels (Invercargill), 9pts, 4; Jocky O'Neill (Alexandra), 8pts, 5; Chris Vickers (Palmerston), 7pts, 6; Ringakaha Paewai (Gore), 6pts, 7; Jack Fagan (Te Kuiti), 5pts, 8; Colin Dennison (Oamaru), 4pts, 9; Paerata Abraham (Masterton), 3pts, 10; Duncan Higgins (Blenheim), 2pts, 11; Troy Pyper (Cheviot), 1pt, 12.
Also (1pt each): Maaka Rangiuaia (Mataura), Colin O'Neill (Alexandra), Lionel Taumata (Gore),
Hemi Braddick (Eketahuna), Jake Rangiuaia (Mataura), Matene Mason (Masterton), Brett Roberts (Mataura), Gavin Mutch (Dannevirke), Duncan Leslie (Owaka), Hugh De Lacy (Parnassus), Willy McSkimming (Oamaru), David Gordon (Masterton), Beau Guelfi (Gisborne), Ant Frew (Pleasant Point), Jordan Boyes (Owaka), Taare Edwards (Ashburton).