diff --git a/papers/doc/7-systems/x1_010.md b/papers/doc/7-systems/x1_010.md
index 952e4231..83587a2b 100644
--- a/papers/doc/7-systems/x1_010.md
+++ b/papers/doc/7-systems/x1_010.md
@@ -1,6 +1,6 @@
 # Seta/Allumer X1-010
 
-One of sound chip originally designed by Seta, mainly used at their arcade hardwares at late-88 to early-2000s.
+One of sound chip originally designed by Seta, mainly used at their arcade hardwares at late-80s to early-2000s.
 it has 2 output channel, but no known hardware using this feature for stereo sound.
 later hardware paired this with external bankswitching logic, but its logic is not emulated now in current furnace revision.
 Allumer one is just rebadged Seta's thing for use in their arcade hardwares.