Buck disappeared from the straight hunt leaderboard, ironically being displaced by Chrystal and Trix, with Chrystal also climbing on to the zig zag leaderboard with Nell.
Originally from Banks Peninsula, Manson has previously contested only four national or island championships runoffs, dating back to 2001 when he won the North Island zig zag title in his top-seven debut at Gisborne.
He also won a South Island short head and yard title at Geraldine four years ago.
He was fourth in both resulting national runoffs and remains determined to collar a green tie, the symbol of national championships supremacy, although he did win a separate national yard dog title in 2004.
Manson said it was "pretty cool" all-round to have been on three leaderboards at this level simultaneously for the first time, to be doing it with such a young team, and to be competing with the family from Little River — father Neill and brothers Sam and Ben, all staying together at a motel in Blenheim.
Ben Manson, who has twice been runner-up in national title runoffs, qualified this year with two heading dogs and one huntaway, and joined the long head leaderboard yesterday with Billy.
Sam Manson is running two huntaways, and their father one huntaway.
Neil Manson has contested two national title runoffs, and Sam Manson one South Island championships runoff.
"I'm getting a bit of a ribbing at the moment," Tom Manson said before yesterday's runs started in morning frost.
He was hopeful he would hold his places on the leaderboards with even more family representation in a week expected to remain fine throughout.
"The weather's been awesome," he said. "And I'm stoked."
Manson was heading a North Island domination of the championships, with all seven places in each hunt held by teams which had crossed Cook Strait a few days earlier, the straight hunt leaderboards having only three South Island combinations, and the short head and yard four.
One pair of first-day performers to disappear from the leaderboards was long head titleholders Bob Bruce and Cheat, of Te Aute, but they still have a short head and yard run to go. Both 2018 champion huntaways, zig zag champions Dave Stuart and Gus, of Ashhurst, and straight hunt champions Vaughan Marfell and Torque, of Masterton, were also out of the running to defend their titles.
Poverty Bay trials legend Merv Utting, created an MNZM in the Queen's Birthday Honours in 2016 and who has three dogs at the championships, kept his eyes on at least a seventh national championships title with Prince on the short head and yard leaderboard.
Leaderboards at 4pm on Day 3
South Island and New Zealand sheep dog championships, Meadow Bank Farms, Omaka, Marlborough, May 28-June 2.
Long head (153 runs): Tom Manson (Raupunga), Pip; Murray Child (Maungakaramea), Dice; Leo Edginton (Tolaga Bay), Kim; Brian Dickison (Gore), Ash; Ben Manson (Little River), Billy; Lloyd Smith (Palmerston), Samantha; Eion Herbert (Tapawera), Bell.
Short head and yard (123 runs): Steve Kerr (Fairlie), Ben; Leo Edginton (Tolaga Bay), Dave; Graeme Brier (Piopio), Sumo; Merv Utting (Gisborne), Prince; Guy Peacock (Dannevirke), Chief; Maurice Haakma (Ward), Brian; Kevin Lamont (Cheviot), Trump.
Zig zag hunt (236 runs): Tom Manson (Raupunga), Spud; Scott McRae (Wellsford), Toby; Mark Lourie (Whangarei), Bella; Gerard Brown (Dannevirke), Brew; Alex Matthews (Wanganui), Rex; Clark Chrystal (Tutira), Nell.
Straight hunt (250 runs): Joshua Brennan (Rangiwahia), Hung; Trevor Rumbal (Taumarunui), Thug; Rebecca Baynes (Wairoa), Tom; Alex Matthews (Wanganui), Bonnie; Murray Child (Maungakaramea), Ralf; Clark Chrystal (Tutira), Trix; Leo Edginton (Tolaga Bay), Robert.