Hakuho and Kakuryu grabbed a share of first place Friday at the Spring Grand Sumo tournament after sole overnight leader Aoiyama suffered his second loss.
The Mongolian-born grand champions sit alongside the rank-and-file grappler at 11-2 following an action-packed Day 13 at Edion Arena Osaka.
Hakuho overpowered fellow title contender Asanoyama in the day's marquee bout, while Kakuryu compounded struggling ozeki Takakeisho's woes.
No. 13 maegashira Aoiyama, meanwhile, may have blown his best shot at an Emperor's Cup following an underwhelming loss to No. 9 Takonosho.
(Hakuho (L) defeats Asanoyama.)
In the day's final clash, Hakuho drove Asanoyama back to the straw and resisted the sekiwake's last-ditch attempt at a pull down to claim victory by push out.
Despite being denied a share of the lead, Asanoyama (10-3) can still obtain the 12 wins he needs to meet one of the benchmarks for promotion to ozeki.
Kakuryu used quick footwork to outmaneuver Takakeisho, who has looked far from his best at the current tournament, which is being held without spectators due to the coronavirus crisis.
As the pair exchanged blows, Kakuryu secured a shallow belt grip and denied Takakeisho room to wind up for his favored thrusting attack before hoisting the ozeki over the straw.
The loss leaves Takakeisho (6-7) dangerously close to a losing record that would see him contest the next tournament as a demotion-threatened "kadoban" ozeki.
(Kakuryu (R) defeats Takakeisho.)
Aoiyama started the day just three wins away from his maiden championship following Hakuho's upset loss to sekiwake Shodai the previous day.
But the big Bulgarian was barely in the contest against Takonosho, succumbing to a push out straight from the jump.
Following the opening collision, Aoiyama half-heartedly tried to pull down Takanosho (10-3), but the smaller wrestler kept his balance and easily drove his way to victory.
No. 3 Mitakeumi stayed one win off the pace at 10-3 by forcing out No. 7 Takarafuji (8-5).
A two-time Emperor's Cup-winner, Mitakeumi is aiming to return to the three "sanyaku" ranks below yokozuna. He lost to Aoiyama on Day 12.
(Enho (top) and Daieisho)
A day after stunning Hakuho, Shodai withstood a spirited challenge from No. 4 Abi to move closer to a winning record at 7-6.
Desperate to avoid a critical eighth loss in the 15-day tournament, Abi opened with a flurry of thrusts that left Shodai teetering at the edge.
But just as he did against Hakuho, Shodai managed to stay inside the straw before rallying back, eventually toppling Abi (5-8) with a frontal push down.
Komusubi Endo also kept a winning record in his sights, improving to 7-6 by beating No. 6 Kagayaki.
Following a solid collision, Endo gained a belt hold that enabled him to force out Kagayaki (7-6) and continue his recent head-to-head dominance against the maegashira.
Komusubi Hokutofuji continued his disappointing tournament, dropping to 3-10 with a force-out loss to No. 5 Ryuden (5-8).
Among the rank and file, No. 5 Onosho and No. 12 Ikioi secured winning records at 8-5 with victories, respectively, against No. 11 Terutsuyoshi and makuuchi-division debutant Kotonowaka (both 7-6).