"I've done a bit of everything in the past but showjumping is the priority these days," Buchanan said.
Familiarity with her horse, Wishful, was a key factor in her success.
That she has been coached by former World Cup rider, Julie Davey, in Hastings since the beginning of the year was another.
"Izzy [Wishful's nickname] and I have a pretty good rapport after being together for the past three years," Buchanan said.
She is preparing for her first Horse of the Year Show appearance in Hastings next March. This weekend she will compete at the annual Maraekakaho Sports Day and, later this summer, at Tuki Tuki Sports Day.
In my family, mum [Belinda] and I do equestrian together and dad [Alister] and my brother Mark do motocross together. When we gather around the dinner table on a Sunday night after our busy weekends, we find out how everybody did,
Buchanan said.
The winning Woodford House Black team consisted of multiple national dressage champion Willa Aitken, Mollie Moffett, Annabell Kerr and Hereworth School student Tim Wilson, who was drafted in to the team.
For Aitken, who has competed in the event since her Year 7 days, she got the winning farewell she wanted in her final appearance at the show.
In addition to helping her team win the premier title, Aitken retained her level three A dressage title.
Next year will see the 25th edition of the annual event, which will provide an extra incentive for Woodford House to complete another clean sweep in the tussle for the premier title.
One of yesterday's highlights was the five-way tie for first in the glamour showjumping event, which ended the programme, the two-fence shootout.
The five were 1m 10cm individual showjumping winner Ruby Mason of Napier Girls' High School on Mr Acho; Julia Hyslop of Woodford House on The Mighty Quinn; Iona College's Molly Prenter on Rump Shaker; Havelock North Intermediate School's Grace Stevenson on Tallyho Reuben James; and Feilding High School's Blake Davis on Toby.
Results, top 4 overall: Woodford House Black (Willa Aitken, Mollie Moffett, Annabell Kerr, Tim Wilson) 1; Woodford House Silver (Clementine Coates, Bella Ladbrook, Milly Waldin, Lucy Buchanan) 2; Woodford Red 3; Napier Girls' High School 4.
Individual showjumping champions: 80cm, Buchanan 1; Ladbrook 2; Kendyll Miller (Havelock North High School) 3. 95cm, Jackie Gesen ( ) 1; Phoebe Burns (Woodford House) 2; Anna Rasmussen ( ) 3. 1m10, Ruby Mason (NGHS) 1; Tessa Wallace (Woodford House) 2; Moffett 3.
Dressage: Level One Test 1C group A, Darien Dalziel- Smith 1; Grace Stevenson 2; Tessa Wallace 3. Test 1C group B, Rebecca Robertson 1; Zara Waldin 2; Poppy Renton 3; Test 1C Group C, Victoria Haig 1; Emilia Burkholz 2; Madison Benbow 3. Test 2A, Emma Matches 1; Isabella Collier 2; Annabel Kerr 3. Test 3A, Willa Aitken 1; Mollie Moffett 2; Mackenzie Heaton 3.