My 7 time great-grandparents as named above were married 1700's. In trying to research marriage dates and death dates I noticed something interesting. Tuomas born approximate 1711 and died according to the Kähkönen family book about 1740 but a Hiski death record shows he was buried 15 Dec 1744 Jutta, Kuhmo, Oulu. age was 33 years. He died a year AFTER the last child he and Sigrid had which was Thomas Kähkönen born on 07 Mar 1743, probably in Kuhmo. I think Sigrid may have remarried but I am unable to find any information about her after the birth of the last child.
Sigrid was born approximately 1700-1709 Kuhmo, Oulu. Her father Eskil Huotari (b.1686-Lentua, Kuhmo - d. 1741 Kuhmo) and her mother Carin Johansdr Merilainen I found (b.1699 Kuhmo - d. 11 Apr 1781 Korpisalmi 1, Kuhmo, Oulu)..
What makes the research so hard, as you may know, there was a devastating fire in Kuhmo in which a lot of records were lost, some saved and while Kuhmo was rebuilding records were entered in Sotkoma.
Sigrid's death date would be the more important piece of information I would hope you could find. As for the marriage, I know that the first child that Sigrid and Tuomas had was born 15 Jan 1731 so they may have married a couple of years before that birth and Sigrid may have remarried a couple of years after the burial of Tuomas which was 1744 aprox.
If all you can find is Sigrid's death date and place you will have completed the research.
Good Luck and thank you.
Janice