14 strokes
                                                    
                        Jouyou kanji
            Taught in 11th grade
    
                                            go upstream, retrace the past
Kun'yomi
- さ - か - の - ぼ - る - to go upstream ②to go back (to the past or origin) 
On'yomi
- ソ 
- サク 
Character Breakdown
go upstream, retrace the past
さかのぼ.る ソ サク (11th)
conjunction (astronomy), first day of month, north
ついたち サク たち (Kentei Pre-1, N1)
References
| Unicode hex code | 9061 | 
| JIS X 0208 | 1-33-44 | 
| Nelson, A. Classic Nelson | 4727 | 
| Haig, J. New Nelson Japanese-English Character Dictionary | 6094 | 
| Halpern, J. New Japanese-English Character Dictionary | 3257 | 
| Halpern, J. Kodansha Kanji Dictionary | 4040 | 
| Halpern, J. Kanji Learners Dictionary (Kodansha), 2nd edition (2013) | 2785 | 
| Heisig, J. Remembering The Kanji | 2847 | 
| Heisig, J. Remembering The Kanji, Sixth Ed. | 2111 | 
| Morohashi Daikanwajiten | 39048X | 
| Spahn and Hadamitzky Kanji and Kana (2011 edition) | 1989 | 
| Tuttle Dictionary Descriptor Code | 3a10.2 | 
| Four corner code | 3730.2 |