What Did Yokohama-Odesa and Kyoto-Kyiv Actually Agree To As Sister Cities?

Two Japan-Ukraine municipal sister-city partnerships appear in the Council of Local Authorities for International Relations (CLAIR)’s sister-city database: the City of Yokohama and the City of Odesa, from July 1, 1965, and Kyoto City and the City of Kyiv, from September 7, 1971. Both were concluded before Japan and Ukraine established diplomatic relations in 1992 (that history is covered in the Japan-Ukraine timeline).

You often see the phrase “became sister cities” in the news. So what does such a partnership actually commit the parties to? And is concluding a partnership the same thing as keeping the exchange alive? We look at the two partnerships’ records, broken down into the documents involved, their purpose, who runs them, and their actual track record.

There Is No Legal Definition of “Sister City”

CLAIR’s “Sister (Friendship) Municipality Q&A” opens by stating this directly: there is no legal definition of a sister (friendship) municipality. This is thought to be because exchange happens through the free-spirited contact of people with people, which does not lend itself to definition.

That said, CLAIR treats a relationship as a “sister (friendship) municipality” for statistical purposes if it satisfies all three of the following criteria.

• There is an agreement document signed by the heads of both municipalities
• The scope of exchange is not limited to a specific field
• The partnership has been approved by the municipal assembly (because exchange is thought to require some budgetary measure)

Kyoto City also cites these same three requirements on its own “What Is a Sister City” page. According to CLAIR, Japan’s first sister-municipality partnership was Nagasaki City and Saint Paul, Minnesota, in December 1955, and the number of partnerships now exceeds 1,700. Whether called a “sister city,” “friendship city,” or “friendship exchange city,” relationships that satisfy the three criteria are treated the same way. Separately from its sister cities, Kyoto City has also established a “Partner City” category, for civic exchange centered on a specific field — because not limiting the field is one of the conditions for a sister city.

The Agreement Document Says No More Than “Friendship”

So what is written in that agreement document? According to CLAIR’s Q&A, its title varies — “pact,” “declaration,” “joint declaration,” “friendship agreement,” and so on — and the body typically states friendship and mutual understanding between the two countries and their citizens. Discussions about the specific substance of future exchange may be made into a separate agreement apart from the partnership document itself, and it is said to be safer to keep concrete, individual matters out of the partnership document and handle them separately.

Both mayors sign the agreement document, and the date of signing usually becomes the partnership date as-is. The document’s effect does not change even when the mayor changes.

In other words, the sister-city agreement document itself is, in most cases, not a document promising “who will do what, by when.” It is a confirmation of the intent to form a friendly relationship. Anything concrete, if it exists at all, is written in a separate document.

What Documents Formed the Two Partnerships?

CLAIR’s database records, for each partnership, the “basis for the partnership date,” whether a “partnership agreement document” exists, and any “partnership committee or similar organization.” Placed side by side, the two partnerships are recorded quite differently.

Item	City of Yokohama – City of Odesa	Kyoto City – City of Kyiv
Partnership date	July 1, 1965	September 7, 1971
Basis for the date	Not recorded	The day the two mayors signed the declaration
Partnership agreement document	“None”	“Exists” (titled: Sister City Declaration)
Partnership committee, etc.	Yokohama-Odessa Friendship Committee (established July 25, 1966)	None
How it came about (each city’s account)	A proposal from the City of Odesa in 1964; a shared bond as international port cities that had both experienced recovery from wartime devastation	Proposed in 1958 by the Soviet ambassador to Japan to the Mayor of Kyoto, formally proposed by letter from the Mayor of Kyiv the following year

The “None” in Yokohama’s column is the record as it appears in CLAIR’s database. What document, if any, was exchanged when the partnership was formed cannot be confirmed on the City of Yokohama’s own official pages. On the Kyoto side, the city explains that the Mayor of Kyoto visited Kyiv in 1971 and held a “Sister City Formation Declaration” ceremony, and CLAIR’s data records that the partnership was approved by the city assembly at that time. However, the text of the declaration itself has not been made public.

Another Document That Wrote In a Purpose and a Deadline

An example of a concrete commitment appears in 2023. On March 16, 2023, Yokohama and Odesa concluded a “Memorandum on Technical Cooperation for Sustainable Urban Development.” The City of Yokohama has published the full text of the memorandum in its press release.

The preamble states that the two cities have built up exchange in administration, culture, healthcare, and other fields since the sister-city partnership of July 1, 1965, and that after Russia’s full-scale invasion of Ukraine began on February 24, 2022, Yokohama provided emergency humanitarian assistance, such as supplying mobile water-purification equipment and cold-weather clothing. On this basis, the two sides agreed on three things.

• To advance cooperation on the recovery, reconstruction, and sustainable development of urban infrastructure in Odesa and its surrounding cities
• To share necessary information with each other, within the bounds of each country’s laws and regulations and with due regard for security interests
• To decide the methods and content of cooperation through separate consultation between the two sides

The memorandum takes effect from the date of signing, and is stated to be “valid until March 31, 2026.” It can be renewed if both sides evaluate the results of the cooperation and agree. It was drawn up in Japanese, Ukrainian, and English, and provides that the English version governs in the event of a difference in interpretation.

If a sister-city agreement document is an open-ended declaration of friendship, this memorandum is a document with a field (recovery and reconstruction of urban infrastructure), a deadline, and a review procedure. Even so, how much is actually done, and to what extent, is left to “separate consultation.” Concluding the memorandum, and each individual project actually being carried out, are two different things that need to be confirmed separately.

There is also a post-partnership document between Kyoto City and the City of Kyiv. According to Kyoto City’s record of exchange, in January 2011, during a welcome event for a visit by the President of Ukraine to Kyoto, a signing ceremony was held for a “Protocol on Cooperation Between the City of Kyiv and Kyoto City,” and both mayors again signed a protocol during a visit that September marking the 40th anniversary of the partnership. The text of these protocols has not been made public on Kyoto City’s official pages.

Who Is Actually Running This?

The mayors sign the partnership document, but it is other people who run the day-to-day exchange.

On the city side, the international-exchange department serves as the point of contact — though its name changes. Looking at the City of Yokohama’s press releases related to Odesa, the department in charge was the International Affairs Bureau’s International Cooperation Division in March 2023, and the International Affairs Bureau’s Global Network Promotion Division in August 2025; the contact point on the Yokohama Ukraine Support Portal is the Policy and Global Affairs Bureau’s Global City Strategy Division. Kyoto City’s July 2026 announcement was handled by the General Planning Bureau’s International City Co-creation Promotion Office.

Citizens are involved too. According to the City of Yokohama, a citizens’ group, the Yokohama-Odessa Friendship Committee, was formed the year after the partnership, in 1966, and received an award from a Ukrainian academic organization in January 2004. Kyoto City’s records state that the “Kyoto-Kyiv Exchange Association” was founded in June 2002. Since 2022, the recipient of donations for Kyoto City’s support of Kyiv has been the “Sister City Kyiv Support Project Executive Committee.”

How Should the Activity Record Be Read?

Looking at Yokohama’s published “History of Exchange with the City of Odesa (1965–2014),” there were exchanges of trade delegations, citizen groups, sports teams, and theater troupes almost every year from the late 1960s through the late 1980s and early 1990s. A dispatch of a medical delegation began in October 1991. From the 2000s on, the record shifts mainly to anniversary events every five years. In 2011, following the Great East Japan Earthquake, students and citizens of Odesa sent condolence donations to the disaster area through the City of Yokohama.

Since February 2022, the record has become dense again: the supply of mobile water-purification equipment to Odesa; the temporary hosting of children from an Odesa judo club from July to August 2022; the speech by the Mayor of Odesa at a plenary session of the Yokohama City Council and the signing of the memorandum in March 2023. In July 2024, Yokohama and the United Nations Development Programme (UNDP) agreed to cooperate on Ukraine support, supporting the recovery of Odesa’s Nursery School No. 141, which had been damaged by a blast. According to the City of Yokohama, this was the first time UNDP had concluded this kind of cooperation agreement with a municipality outside Ukraine. In August 2025, a crowdfunding campaign began to furnish this nursery school with playground equipment and other items.

Kyoto City’s record follows a similar shape. On the City of Kyiv page, the exchanges listed — the 30th anniversary in 2001, the 40th in 2011, a visit by the Mayor of Kyiv in 2016, a Kyoto City delegation’s visit to Kyiv in 2017 — center on anniversaries and visits by dignitaries, and the list ends in October 2018. Since 2022, a separate page continues with a joint letter from the mayor and the chair of the city council (February 16, 2022 and February 24, 2023), an online meeting between the two mayors (April 6, 2022), a remittance of ¥60,799,548 in donations (May 13, 2022), and shipments of blankets, heat packs, and emergency medical supplies. On July 28, 2026, 1,400 used learning laptops from city elementary and junior high schools departed for shipment to schools in Kyiv (scheduled to arrive mid-to-late October).

What the two records show is that while the partnerships themselves have continued unbroken for 60 and 55 years, the density of exchange has varied greatly by period. And the list on each official page is what the city chose to record. The absence of an entry for a given year does not mean nothing happened, and anything after the list’s last update date will not appear there.

Concluding an Agreement, and Keeping Exchange Alive

A sister-city agreement document remains in effect even when the mayor changes. In that sense, the partnership continues. But exchange costs money, which is exactly why CLAIR makes municipal-assembly approval a condition for a sister city. The department in charge and citizens’ groups are the ones who actually run things, and concrete cooperation is sometimes decided in a separate document that sets out a purpose and a deadline.

The next time you come across a sister-city story or news item, it helps to look at four things separately: what document was exchanged, and is it public; is that document a declaration of friendship or an agreement with a field and a deadline; which department and group are currently running it; and how far the dated record of activity extends.