In the 1980s, Charles Forgy developed a successor to the Rete algorithm named Rete II. Unlike the original Rete (which is public domain) this algorithm was not disclosed. Rete II claims better performance for more complex problems (even orders of magnitude), and is officially implemented in CLIPS/R2, a C/++ implementation and in OPSJ, a Java implementation in 1998. Rete II gives about a 100 to 1 order of magnitude performance improvement in more complex problems as shown by KnowledgeBased Systems Corporation benchmarks.