The 9th-10th International Conference on the Theory and Practice of Natural Computing (TPNC 2020 & 2021) invites researchers to submit poster presentations. TPNC 2020 & 2021 will be held in Tsukuba, Japan on December 7-10, 2021. See: https://irdta.eu/tpnc2020-2021/ Poster presentations are intended to enhance informal interactions with conference participants, at the same time allowing for in-depth discussion. TOPICS Presentations displaying novel work in progress on computational principles, models and techniques inspired by information processing in nature are invited. Posters do not need to show final research results. Work that might lead to new interesting developments is welcome. KEY DATES Poster submission deadline: October 31, 2021 Notification of poster acceptance or rejection: November 7, 2021 SUBMISSION Please upload a .pdf submission to: https://easychair.org/conferences/?conf=tpnc20202021 It should contain the title, author(s) and affiliation, and should not exceed 500 words. PRESENTATION Posters will be allocated 10 minutes each in the programme for oral presentation. Moreover, they will remain hanging out during the whole conference for discussion. PUBLICATION Posters will not appear in the LNCS proceedings volume of TPNC 2020 & 2021. However, they will be eligible for submission to the post-conference journal special issue in Neural Computing and Applications (2020 JCR impact factor: 5.606). REGISTRATION At least one author of each accepted poster must register to the conference by November 14, 2021. The registration fare is reduced: 285 Euros. It gives the same rights all other conference participants will have (attendance, copy of the proceedings volume, coffee breaks, lunches). Contributors of regular papers who in addition get a poster accepted must register for the latter independently.