The home side are 18th and are one place and one point from safety with 14 points, while the visitors are second-last in 19th place and also have 14 points.
Match preview
After 17 games the hosts are averaging just 0.82 points per game this term, and this is the third consecutive season that this figure has been in decline.
In fact, this is Tosu's lowest average return since returning to the top flight in 2012.
Their precarious position will be of serious concern to manager Kenta Kawai, although he does at least have the comfort of a game in hand over 17th-placed Shonan Bellmare.
Kawai's side have conceded 30 goals this season and this makes them the division's fourth-worst defensive side, while they also have the league's joint-third worst goal difference.
Tosu have been led by Kawai since January 2022 and although they have won two of their last five games in the J1 League they have lost their last three without scoring, and have lost 13 of their last 20 matches.
Though the hosts have collected 10 of their 14 points at the Ekimae Real Estate Stadium, their form at home has not been particularly consistent given they have lost nine of the last 13 league fixtures at their own stadium.
Visitors Kyoto Sanga have played 18 top-flight games this season, concededing 31 goals and scoring just 15 times, six less than Tosu.
They are unbeaten in their last three league games, with two draws and a win last time out against Consadole Sapporo on Saturday, but prior to this they did lose eight of their last nine.
Manager Kwi-Jea Cho has been in charge since February 2021 and was able to help the club return to the top flight in 2022.
Although Kyoto Sanga are at risk of relegation, this is their third consecutive season in the J1 League, and Cho should be commended for his work considering his side had spent 11 seasons in Japan's second division between 2011 and 2021.
Interestingly, though his team's away record this campaign has not been particularly strong, they have earned 10 of their 14 points on the road and this makes them the league's 13th-best away team based on points won, contrasting with their home form in which they rank last.
Games between Kyoto Sanga and Sagan Tosu have usually been high scoring affairs, with the last four top-flight encounters seeing 15 goals scored and two wins apiece.
Sagan Tosu J1 League form:
L
W
W
L
L
L
Kyoto Sanga J1 League form:
L
L
L
D
D
W
Team News
The hosts are set to be without attacking midfielder Fuchi Honda as he recovers from a lateral meniscus tear, an injury that has kept him out since May 2023.
Midfielder Yoshiki Narahara is also out for Sagan Tosu due to the cruciate ligament injury he suffered in September 2023.
Goalkeeper Masahiro Okamoto is not expected to return until August after picking up a calf injury in early June.
As for the away side, right-back Kyo Sato was forced off with an injury during his side's most recent match against Sapporo and it remains to be seen if he his ready for this weekend's clash.
Elsewhere, they have no other injury concerns to contend with, but centre-back Hisashi Appiah Tawiah will have to be cautious as he is at risk of suspension if he picks up another yellow card.
Sagan Tosu possible starting lineup:
Il-Kyu; Harada, Kimura, Kim, Maruhashi; Kawahara, Tezuka; Togashi, Kikuchi, Yokoyama; Ryan
Kyoto Sanga possible starting lineup:
Gu; Fukuda, Miyamoto, Y. Suzuki, T. Suzuki; Kawasaki, Kaneko, Hirato; Toyokawa, Hara, Matsuda
We say: Sagan Tosu 1-2 Kyoto Sanga
Considering the hosts have lost their last three league fixtures, it is feasible that they could struggle once again on Saturday.