South Korea has custom-made furniture for Friday's summit between President Moon Jae-in and the North's leader Kim Jong Un -- with chairs featuring disputed islands controlled by Seoul but claimed by Tokyo.
One thing the rival Koreas share is a resentment of Japan, which imposed brutal colonial rule on the peninsula from 1910 to 1945, and the gesture is likely to irritate Tokyo.
Japan has already lodged a strong protest over photos of a summit dessert dish which also marks the disputed islands.
Japan and the South are both US allies but their relationship is strained by historical and territorial issues including Dokdo -- islands controlled by Seoul but claimed by Tokyo, which calls them Takeshima.
The new walnut chairs to be used by the two leaders at Friday's summit at Panmunjom in the Demilitarized Zone (DMZ) both feature a map of the peninsula.
The tiny disputed islands are clearly marked, pictures released by the presidential Blue House showed Wednesday.
Photographs of the dishes planned for the summit dinner show a mango mousse dessert that also displays a stylised map of the peninsula with the islands prominently marked.
Japanese media reported on the dessert map, though not the chairs, on Wednesday, and Tokyo said it had formally complained to South Korea.
The Japanese foreign ministry said it had lodged a protest Tuesday with its counterpart in Seoul as well as with Seoul's embassy in Tokyo.
"It is regrettable and we cannot accept this in light of our position over the sovereignty of Takeshima," said a ministry spokesman, reading from a brief prepared statement.
"We issued a strong protest" and reiterated Japan's position to South Korea, the statement said.
Symbolism also abounds in other aspects of the summit layout, with the seven-strong delegations meeting in the Peace House around an oval table 2,018 millimetres wide to mark the year.
"The oval table reflects the wish to see the North and the South sit down together and hold frank talks without any feeling of distance despite 65 years of division," the presidential Blue House said.
Traditional white porcelain vases will decorate corners of the room, filled with flowers including peonies to symbolise greetings, daisies for peace, and wild blooms from the DMZ.
The two previous inter-Korean summits in 2000 and 2007 both took place in Pyongyang.
It is not the first time Seoul has made a point of including the islands in diplomatic processes.
When US President Donald Trump visited Seoul last year, his meal included a prawn caught in waters around Dokdo, sparking protests from Tokyo.
At the Winter Olympics opening ceremony in February, the two Koreas marched together behind a unification flag that did not include Dokdo, after Tokyo denounced the emblem used at a practice event. Japan's chief Cabinet secretary Yoshihide Suga described that flag, which did show the islands, as "unacceptable".