Men's singles
2023 Keio Challenger
Champion	Yosuke Watanuki
Runner-up	Yuta Shimizu
Score	7–6(7–5), 6–4

Christopher O'Connell was the defending champion^[1] but chose not to defend his title.

Yosuke Watanuki won the title after defeating Yuta Shimizu 7–6^(7–5), 6–4 in the final.

Seeds

Draw

Finals

	Semifinals							Final
	1	Yosuke Watanuki	6	62	6
	3	Michael Mmoh	4	77	0
								1	Yosuke Watanuki	77	6
									Yuta Shimizu	65	4
		Yuta Shimizu	w/o
	Q	Yasutaka Uchiyama

Top half

	First round							Second round							Quarterfinals							Semifinals
	1	Y Watanuki	6	6
		Y-h Hsu	3	3				1	Y Watanuki	6	6
	Q	C Sinclair	3	2				LL	M Erhard	4	3
	LL	Mathys Erhard	6	6											1	Y Watanuki	3	6	6
	Q	A Holmgren	4	1											LL	G Fonio	6	2	1
	LL	G Fonio	6	6				LL	G Fonio	4	77	6
	WC	R Noguchi	2	2				8	L Riedi	6	64	4
	8	L Riedi	6	6																		1	Y Watanuki	6	62	6
	3	M Mmoh	6	6																		3	M Mmoh	4	77	0
		M Echargui	1	2				3	M Mmoh	6	5	77
		G Blancaneaux	6	61	6				G Blancaneaux	4	7	63
	Q	O Jasika	4	77	3										3	M Mmoh	78	2	6
	Q	K Ivanovski	6	5	6										6	L Nardi	66	6	4
		Z Bergs	1	7	2			Q	K Ivanovski	2	4
	LL	Y-s Chung	2	4				6	L Nardi	6	6
	6	L Nardi	6	6

Bottom half

	First round							Second round							Quarterfinals							Semifinals
	7	M Polmans	6	6
		C İlkel	1	0				7	M Polmans	4	4
		J Jung	4	5					Y Shimizu	6	6
		Y Shimizu	6	7												Y Shimizu	79	61	77
	Alt	A Çelikbilek	6	3	2											C Wong	67	77	64
		C Wong	2	6	6				C Wong	w/o
		Z Kolář	2	77	2			4	J Duckworth
	4	J Duckworth	6	64	6																		Y Shimizu	w/o
	Q	N Nakagawa	65	6	2																	Q	Y Uchiyama
		A Martin	77	1	6				A Martin	6	4	5
	WC	Rei Sakamoto	4	3					L Tu	2	6	7
		L Tu	6	6												L Tu	61	5
	Q	Y Uchiyama	6	6											Q	Y Uchiyama	77	7
	WC	M Imamura	1	1				Q	Y Uchiyama	2	6	6
		S-c Hong	78	78					S-c Hong	6	4	4
	2	J Rodionov	66	66

References

External links

• Main draw
• Qualifying draw