#1 Singles and Albums in 2020 according to Oricon
From December 18, 2019 to December 16, 2020. Click on the # for that week to view the top 30 albums and singles.
Note: 'Week Sales' means the number of units that the product sold to get to #1 for that week. Usually, this is the product's first week sales, but not always.
| # | Date | Single Artist | Single | Week Sales | Album Artist | Album | Week Sales | 
| 1 | 12.30 | MAMESHiBA NO TAiGUN | Restart | 64,334 | Various Artists | Fate song material | 34,133 | 
| 2 | 01.06 | BOYS AND MEN | Gattan Gotton GO! | 95,327 | Buster Bros!!! | Buster Bros!!! -Before The 2nd D.R.B- | 43,700 | 
| 3 | 01.13 | Takeuchi Mariya | Inochi no Uta (Special Edition) | 6,875 | Katori Shingo | 20200101 | 27,661 | 
| 4 | 01.20 | Poppin'Party | Initial / Yume wo Uchinuku Shunkan ni! | 27,164 | Kimura Takuya | Go with the Flow | 126,831 | 
| 5 | 01.27 | SKE48 | Souyuutoko Aru yo ne? | 289,471 | King Gnu | CEREMONY | 238,047 | 
| 6 | 02.03 | SixTONES vs Snow Man | Imitation Rain / D.D. | 1,328,206 | NCT DREAM | THE DREAM | 40,386 | 
| 7 | 02.10 | STU48 | Mubou na Yume wa Sameru Koto ga Nai | 287,713 | MAD TRIGGER CREW | MAD TRIGGER CREW -Before The 2nd D.R.B- | 49,783 | 
| 8 | 02.17 | SixTONES vs Snow Man | Imitation Rain / D.D. | 44,982 | Sexy Zone | POP × STEP!? | 131,035 | 
| 9 | 02.24 | SixTONES vs Snow Man | Imitation Rain / D.D. | 30,921 | Little Glee Monster | BRIGHT NEW WORLD | 40,268 | 
| 10 | 03.02 | Hinatazaka46 | Sonna Koto Nai yo | 558,219 | AAA | AAA 15th Anniversary All Time Best -thanx AAA lot- | 115,459 | 
| 11 | 03.09 | Hey! Say! JUMP | I am / Muah Muah | 206,295 | BTS | Map of the Soul: 7 | 376,879 | 
| 12 | 03.16 | JO1 | PROTOSTAR | 327,187 | NEWS | STORY | 115,130 | 
| 13 | 03.23 | Jaejoong | Brava!! Brava!! Brava!! / Ray Light of Light | 45,820 | GLAY | REVIEW II ~BEST OF GLAY~ | 64,106 | 
| 14 | 03.30 |  |  |  |  |  |  | 
| 15 | 04.06 |  |  |  |  |  |  | 
| 16 | 04.13 |  |  |  |  |  |  | 
| 17 | 04.20 |  |  |  |  |  |  | 
| 18 | 04.27 |  |  |  |  |  |  | 
| 19 | 05.04 |  |  |  |  |  |  | 
| 20 | 05.11 |  |  |  |  |  |  | 
| 21 | 05.18 |  |  |  |  |  |  | 
| 22 | 05.25 |  |  |  |  |  |  | 
| 23 | 06.01 |  |  |  |  |  |  | 
| 24 | 06.08 |  |  |  |  |  |  | 
| 25 | 06.15 |  |  |  |  |  |  | 
| 26 | 06.22 |  |  |  |  |  |  | 
| 27 | 06.29 |  |  |  |  |  |  | 
| 28 | 07.06 |  |  |  |  |  |  | 
| 29 | 07.13 |  |  |  |  |  |  | 
| 30 | 07.20 |  |  |  |  |  |  | 
| 31 | 07.27 |  |  |  |  |  |  | 
| 32 | 08.03 |  |  |  |  |  |  | 
| 33 | 08.10 |  |  |  |  |  |  | 
| 34 | 08.17 |  |  |  |  |  |  | 
| 35 | 08.24 |  |  |  |  |  |  | 
| 36 | 08.31 |  |  |  |  |  |  | 
| 37 | 09.07 |  |  |  |  |  |  | 
| 38 | 09.14 |  |  |  |  |  |  | 
| 39 | 09.21 |  |  |  |  |  |  | 
| 40 | 09.28 |  |  |  |  |  |  | 
| 41 | 10.05 |  |  |  |  |  |  | 
| 42 | 10.12 |  |  |  |  |  |  | 
| 43 | 10.19 |  |  |  |  |  |  | 
| 44 | 10.26 |  |  |  |  |  |  | 
| 45 | 11.02 |  |  |  |  |  |  | 
| 46 | 11.09 |  |  |  |  |  |  | 
| 47 | 11.16 |  |  |  |  |  |  | 
| 48 | 11.23 |  |  |  |  |  |  | 
| 49 | 11.30 |  |  |  |  |  |  | 
| 50 | 12.07 |  |  |  |  |  |  | 
| 51 | 12.14 |  |  |  |  |  |  | 
| 52 | 12.21 |  |  |  |  |  |  |