I have a friend from Austin who ran for city council there as a Libertarian. When he described how the city council was elected, I was surprised. So, rather than elect all councillors on one ballot, each council seat is elected on separate ballots. Certain groups gravitate to certain ballots, like Hispanics will all be on one ballot. Do I remember correctly? It seems like a strange system.
That is correct, Positions 2, 5, and 6 along with mayor were contested in one election; while positions 1, 3, and 4 were contested in another year. An oddity was that the terms were for three years, so that the city had elections 2 out of 3 years.
Houston elects 5 city council members at-large by position, and 11 members by district (previously 9 by district). The at-large positions are sort of tied to race. It has been weakened because of term limits (3 2-year terms) and district elections.
A candidate can be elected to a district race by having a more specific appeal, which might not translate to an at-large election. It is similar to Bobby Rush beating Barack Obama in a congressional race, but Rush probably not electable to the US Senate from Illinois.
Because of term limits, there will be a wide open race with 6 or 7 candidates, when the seat is open. The next election there might be a single challenger, and the candidate might be unopposed the 3rd election. Everyone is saving up for the election they have a chance in. So you might only have one or two at-large seats that are open. A district council member might try to jump to an at-large seat, regardless of who it is reserved for.
In Austin, you will have slating. So they will support a Hispanic candidate for one position, a Black for another. They won't necessarily be the candidates that the Hispanic or Black electorate would have chosen by themselves. It is expensive to run citywide, and to head off a VRA challenge, business leaders agreed not to fund white candidates running for two positions, 5 and 6. In addition, if the minority candidate was reasonably compliant, he might receive funding as well. This began in 1975, with Position 5 as the Hispanic position, and 6 as the Black position. In 1997, a popular Hispanic candidate who would later become mayor, switched to Position 2, but another Hispanic candidate narrowly lost in Position 5. So Position 2 is now the Hispanic position.
As White liberals gradually took over the city council, they would of course avoid running in the two minority positions.
History of Austin Districts