Dominique Josse (France) succeeded in something that was considered as quite impossible: creating a mixed first day cover with the stamps from both France and Japan issued on October 8, 2021 (week of letter writing, mail boxes [T20211008]). In France, access to first day cancellations remains possible about 8 weeks following the official first day date, but Japan does not allow production of items with dates different than the one of the day on which it is cancelled. In other words, Japan first day covers could be obtained only on October 8, 2021, while French cancellations from October 8, 2021 remained possible until around December 8, 2021. Additionally, in this specific case, and in contrary to usual joint issue first days, there was no common joint issue ceremony, no exchange of post staff for this day and therefore no creation of official common joint first day covers. So, Dominique, managed to have access to a few Japanese official first day covers, without cachet, and, when received in France, added the French stamps before asking to the French post to cancel these stamps. Here is the result, magnificent item and quite rare. No idea if other collectors have tried as well and succeeded. To our knowledge, and so far, the number of existing samples must remain below 10. Congratulations Dominique!